Assessing OEM Door Lock Module (DLM) and solenoids

[DMC-81]

Hi there,

As part of the refurb of my doors, can you all help me assess my DLM and solenoids? When I bought the car, the central locking system was unplugged, as most of them are. I haven't attempted to plug it in yet as in want to assess the system first. I removed the DLM and one solenoid today (passenger). I opened the DLM and (separately) tested the solenoid with 12V and it works in both directions. I can move the plunger freely... It's kind of springy. I have yet to test the driver one.

Both units appear not to have the burn signs that I read about. Here are some pics. Can you take a look and see if you notice anything awry?

39069 39070 39071 39072 39073

Assuming that everything is OK, I want to keep the original system as long as possible. However, I understand that the DLM has a flaw. I intend to install an inline 10A fuse in it to protect the solenoids, and adjust the latches and locks per spec. Is there anything else I should do? Replace the 2 relays, etc?

Thanks for your opinions.

[sdg3205]

I wrestled with an original DLM for a long time on a project car. I'd get intermittent lock or unlock, can't recall. In the end i bought new relays from DMCNW. Problem solved. New relays are about $12 and can be soldered into place quite easily.

IIRC, original DLM's would burn out solenoids by a relay sticking. Fusing the DLM will tell you a lot about your situation. I kept blowing 10 amp fuses, so I knew something wasn't right.

[PJ Grady Inc.]

You can't see the points on the relays in the pics but you are probably a candidate for reconditioning these parts to a better than NOS standard which I strongly prefer over aftermarket actuators. We offer better reconditioned modules and solenoids on an exchange basis. If anyone is interested please PM me.
Rob

[DMC-81]

Thanks Dave and Rob. Here are close up shots of the relay points:

39084 39085

If that's what wears/sticks/fuses they seem pretty OK. That gives me hope about the condition of the Driver Soleniod.

I may change the relays if the new ones are an improvement.

Question: Whether I change the relays or not, will the inline fuse protect me ( in theory) of the solenoids burning out from relay failure? I'm not anxious to get locked in the car.

Thanks again.

[David T]

Thanks Dave and Rob. Here are close up shots of the relay points:

39084 39085

If that's what wears/sticks/fuses they seem pretty OK. That gives me hope about the condition of the Driver Soleniod.

I may change the relays if the new ones are an improvement.

Question: Whether I change the relays or not, will the inline fuse protect me ( in theory) of the solenoids burning out from relay failure? I'm not anxious to get locked in the car.

Thanks again.

The short answer is YES. If you use the OEM door lock module and anything goes wrong the 10A in-line fuse will blow rendering the door lock module inoperative. You will be able to lock and unlock, open, and close the doors manually. This advice is for everyone still using the OEM DLM. Either cut a 10A in-line fuse into the big red wire or disconnect the big red wire from the circuit breaker.

[opethmike]

Honestly, just get one of the new door lock modules. Work real nice and don't have the frequent problems of the stock units.

[David T]

Honestly, just get one of the new door lock modules. Work real nice and don't have the frequent problems of the stock units.

A better door lock module will solve many of the problems but not all. You still have to have both doors properly adjusted and the solenoids can't be bad. Some owners just don't want to spend the money to get the better DLM so adding the fuse is a cheap work-around.

[opethmike]

A better door lock module will solve many of the problems but not all. You still have to have both doors properly adjusted and the solenoids can't be bad. Some owners just don't want to spend the money to get the better DLM so adding the fuse is a cheap work-around.

Guru,

I didn't say that the new DLM would solve all of the problem, I said it would solve the problems around the stock DLM.

[PJ Grady Inc.]

Guru,

I didn't say that the new DLM would solve all of the problem, I said it would solve the problems around the stock DLM.

Not really Mike as I've seen a lot of failures with the new modules. They also have about a one second delay before activating the solenoids which I can't get my head around. (No jokes there Miky boy...control yourself!). I think the best fix for now is rebuilding the originals with better relays until Lockzilla's become available again. Wait did I just jinx myself or will the mighty "Zilla" soon return to save the Delorean world from electrical Armageddon? I guess we'll just have to wait and see!
Rob

[Bitsyncmaster]

The design problem with the OEM and original LockZilla was the way they created the time delay for solenoid operation. Both designs used a 1000 uf. capacitor that powered the relay coil. That results in the relay coil voltage slowly dropping which caused the relay contacts to also open slowly and burn the contacts. The LockZilla used 70 amp relays so its contacts may last longer.

[PJ Grady Inc.]

The design problem with the OEM and original LockZilla was the way they created the time delay for solenoid operation. Both designs used a 1000 uf. capacitor that powered the relay coil. That results in the relay coil voltage slowly dropping which caused the relay contacts to also open slowly and burn the contacts. The LockZilla used 70 amp relays so its contacts may last longer.

You might say that as out of hundreds of units sold I can't ever recall one failing....not even after 20 years!
Rob

[DMC-81]

Great discussion so far.

On the question of why not just get a new system? In my case, the answer is aligned with my restoration goal: "mostly correct, with known flaws corrected". If my OEM lock system is in good condition, a small upgrade that addresses the flaw is a good investment in keeping it original. Other than that, a digital controller, launchers, and remotes are very cool! I'm really glad there's 2 options: uprated OEM, or a modern system. Win win!

[sdg3205]

You can get the original equipment to work, it just takes patience. Just swap in new relays and go from there.

[David T]

You can get the original equipment to work, it just takes patience. Just swap in new relays and go from there.

I agree but your answer is too simplistic. It all starts with properly adjusting the doors. Then, if necessary, repairing or replacing the solenoids if they are burnt. Then adding the 10A in-line fuse. The relays burning up are a symptom, not a cause.

[Bitsyncmaster]

The other problem with the OEM and Zilla controller is the standby current draw of 12 ma. This is the main reason people need to install a battery disconnect switch. Elvis posted a circuit change to reduce that standby current which could be implemented on those controllers. I did post a new design a long time ago but there was not much interest so I never made a PCB for it.

[David T]

The other problem with the OEM and Zilla controller is the standby current draw of 12 ma. This is the main reason people need to install a battery disconnect switch. Elvis posted a circuit change to reduce that standby current which could be implemented on those controllers. I did post a new design a long time ago but there was not much interest so I never made a PCB for it.

The current drain only becomes a problem if you either have an already bad battery and/or you don't use the car for over a month. In any case you can still retain the OEM module with that circuit change, it is not very hard to do if you can solder. I agree the best option would be a Lockzilla if you can find one and are willing to pay the price. There are some owners that are very frugal and want to spend the least amount possible. That means fixing what you got. Putting in the battery master switch has other benefits besides eliminating the standby current draw so you may want to do that anyway.

[Elvis]

hey the old power lock thread :-)

use the search !

few dollar of parts and it's not worse or better than that Japanese monster ( believe me or not - I don't care anymore, have other problems)

INSTALL THE FUSE !!!!!!
10 A !!!!


enjoy a working power lock system, mine works since I updated it and ~ 70...100 other, too.

a remote can easily be installed, too. I have two here that are tested on my car and work.

4 wires to solder - done !

PM me if interested.

have a nice weekend

[DMC-81]

Gentlemen, thanks for all the very helpful information.

I will research more, and assess the other solenoid. I'll loop back and post my solution here as well.

[lsoasey]

I'm going through a similar process as DMC-81 of evaluating the door lock module solenoids in my car. I'm interested in upgrading the components within my original Door Lock Module as described by Elvis' nice PDF. Can anyone provide a web link or part number for the a relay replacement which is physically pin compatible with the original relays on the board? I can see that suppliers like Digi-Key have many options which are electrically compatible -- I'm just uncertain on the pin alignment. I haven't been able to find a recommendations here via the forum search. (I'll apologize in advance if it has been posted already. I may not be using the proper combination of keywords...) I think I can find the transistor and resistors.

Thanks!

[Bitsyncmaster]

Your probably going to find a relay rated for the same current for an exact fit on the circuit board (if you can even find one). I would just recommend you inspect the relay points and file them if necessary and add the 10 amp fuse to protect things.

Now if you want to get creative you could wire in a standard 40 amp relay but you would need to cut the DLM box for clearance.

[DMC-81]

I'm going through a similar process as DMC-81 of evaluating the door lock module solenoids in my car. I'm interested in upgrading the components within my original Door Lock Module as described by Elvis' nice PDF. Can anyone provide a web link or part number for the a relay replacement which is physically pin compatible with the original relays on the board? I can see that suppliers like Digi-Key have many options which are electrically compatible -- I'm just uncertain on the pin alignment. I haven't been able to find a recommendations here via the forum search. (I'll apologize in advance if it has been posted already. I may not be using the proper combination of keywords...) I think I can find the transistor and resistors.

Thanks!

Hi there,

I'm still gathering parts for the mod, but here is what I have ordered:

2 x OEM open relays (Tyco/Siemens VKP-15F42). I bought them from Toby at DPNW part # 101420-RO $6.95 each

http://www.delorean-parts.com/Merchant2/merchant.mvc?Store_Code=DPNW&Screen=PROD&Product_Code=101420-RO

(The Digi-Key part # is PB313-ND but it's obsolete )

1 x inline fuse with 10 amp fuse. Toby at DPNW

2 x Darlington Transistor MFG Part No: BD679-NPN Mouser Part #:511-BD679

2 x 10k ohm Vishay Metal Film Resistors - Through Hole. MFG Part No:CCF0710K0JKE36
Mouser Part # 71-CCF0710K0JKE36

Your post has great timing. I got the parts from Toby, but I'm waiting on the Mouser order.

Please, can anyone with electrical expertise comment on my choice of resistor? I think I got the exact Transistor that was in Elvis' instructions.

Cheers,
Dana

[DMC-81]

2 x 10k ohm Vishay Metal Film Resistors - Through Hole. MFG Part No:CCF0710K0JKE36
Mouser Part # 71-CCF0710K0JKE36

Please, can anyone with electrical expertise comment on my choice of resistor?

Sorry, here is the link to the part.... http://www.mouser.com/ProductDetail/Vishay-Dale/CCF0710K0JKE36/?qs=NQWA6AwZmkNSbeldIV%252bliA%3D%3D

Thanks!

[lsoasey]

Hi there,

I'm still gathering parts for the mod, but here is what I have ordered:

2 x OEM open relays (Tyco/Siemens VKP-15F42). I bought them from Toby at DPNW part # 101420-RO $6.95 each

http://www.delorean-parts.com/Merchant2/merchant.mvc?Store_Code=DPNW&Screen=PROD&Product_Code=101420-RO

(The Digi-Key part # is PB313-ND but it's obsolete )

1 x inline fuse with 10 amp fuse. Toby at DPNW

2 x Darlington Transistor MFG Part No: BD679-NPN Mouser Part #:511-BD679

2 x 10k ohm Vishay Metal Film Resistors - Through Hole. MFG Part No:CCF0710K0JKE36
Mouser Part # 71-CCF0710K0JKE36

Your post has great timing. I got the parts from Toby, but I'm waiting on the Mouser order.

Please, can anyone with electrical expertise comment on my choice of resistor? I think I got the exact Transistor that was in Elvis' instructions.

Cheers,
Dana

Dana... This is great! Good timing indeed. I didn't realize that DPNW stocked the appropriate relay, so I'm glad you pointed that out. It just so happens that I placed an order with them online a couple days ago that hasn't been processed yet. I'll try to contact them tomorrow to see if they can simple add this to that order.

Thanks!
-Luke

[kings1527]

I installed the new digital DLM that I ordered from DMCMW along with the new door actuators (I think from DMCNW) over three years ago and they've all functioned perfectly since minute one. FWIW.

[Bitsyncmaster]

Sorry, here is the link to the part.... http://www.mouser.com/ProductDetail/Vishay-Dale/CCF0710K0JKE36/?qs=NQWA6AwZmkNSbeldIV%252bliA%3D%3D

Thanks!

Metal film resistors are better than carbon resistors so that resistor should work fine

[DMC-81]

Metal film resistors are better than carbon resistors so that resistor should work fine

Thanks Dave!

I'll post my progress once I get the parts.

[Elvis]

Dana - I already wrote you - there is absolutely no reason to worry about the resistors !

Same size, same technology or even cheaper - no problem at all !!
Just increase the resistance from 1k to 10k to save standby current .

It doesn't even matter it is a 5.6 k or 15k.
10k was most reasonable from availability, current saving and time between locking and unlocking.

You could even use a smaller sized one because - less current -> less power !
But the size is standard and you can get it from any electronics parts dealer.


Great to see you bought the fuse :-)

[DMC-81]

Dana - I already wrote you - there is absolutely no reason to worry about the resistors !

Same size, same technology or even cheaper - no problem at all !!
Just increase the resistance from 1k to 10k to save standby current .

It doesn't even matter it is a 5.6 k or 15k.
10k was most reasonable from availability, current saving and time between locking and unlocking.

You could even use a smaller sized one because - less current -> less power !
But the size is standard and you can get it from any electronics parts dealer.


Great to see you bought the fuse :-)


Thanks Elvis! Actually, I bought 2 versions of the resistors (they were only 10 cents each), first - one that was 1/8 watt, and second - the one mentioned above that was 1/4 watt. When I got the first 1/8 watt ones, they visually seemed too small, and the 1/4 watt one seemed approximately the same size as the ones in the DLM. (I was concerned about using components that are not up to the task, and maybe burn out etc., so I thought I'd check.

Here is the 1/8 version link: http://www.mouser.com/ProductDetail/Vishay-BC-Components/MBA02040C1002FRP00/?qs=LkqrmUh5PIK5PYXcHU8U2A%3D%3D

So are you saying the 1/8 watt resistor would be better because it would be more efficient at reducing standby power?

Sorry for the rudimentary questions. :facepalm: I'm learning along the way.

By the way, here are all the parts together:
39422

(That's not the fuse that I got from Toby. His is very similar, and but I'll use it elsewhere.)

Cheers,

[Elvis]

The power rating only says what the resistor could withstand

but in this application it does not come even close to the maximum power !


P = U²/ R = 14V * 14V / 10000 V/A = 20mW -> worst case maxixmum power loss on the resistor

1/8 W = 125mW

you see - we are far away from the maximum power that the small resistor could handle


Do you believe me now, that it really does not matter at all ?

[DMC-81]

The power rating only says what the resistor could withstand

but in this application it does not come even close to the maximum power !


P = U²/ R = 14V * 14V / 10000 V/A = 20mW -> worst case maxixmum power loss on the resistor

1/8 W = 125mW

you see - we are far away from the maximum power that the small resistor could handle


Do you believe me now, that it really does not matter at all ?


Thanks for the detailed explanation Elvis! Now I understand. I'll use the 1/8 watt resistor. :thumbup: It's not that I didn't believe you. It's just that I second guessed my shopping based on size. :umm: Now I know a little bit more about these small electronics. I even learned how to read the color bands.

On to de-soldering and soldering! :wrenchin:

[Bitsyncmaster]

Thanks for the detailed explanation Elvis! Now I understand. I'll use the 1/8 watt resistor. :thumbup: It's not that I didn't believe you. It's just that I second guessed my shopping based on size. :umm: Now I know a little bit more about these small electronics. I even learned how to read the color bands.

On to de-soldering and soldering! :wrenchin:

You can use a higher power rated resistor as long as it fits. You just should not exceed the power rating on components. So you can use either the 1/8 watt or 1/4 watt resistor. Nothing will change as far as reliability since your circuit is running the component way lower than the rated max power.

[lsoasey]

I replaced the 2 relays, 2 resistors, and 2 transistors in my DLM last night. In case you don't know about this tool already, I thought I mention that a desoldering pump makes this upgrade really easy.

39478

[DMC-81]

You can use a higher power rated resistor as long as it fits. You just should not exceed the power rating on components. So you can use either the 1/8 watt or 1/4 watt resistor. Nothing will change as far as reliability since your circuit is running the component way lower than the rated max power.

Thanks Dave! I really appreciate the advice from the pros.



I replaced the 2 relays, 2 resistors, and 2 transistors in my DLM last night. In case you don't know about this tool already, I thought I mention that a desoldering pump makes this upgrade really easy.


Thanks for the tip!

[DMC-81]

Well, after a long hiatus, I finally got around to installing these parts in my DLM. Here is a summary...

I first started to de-solder the relays.

41680

One old relay removed...

41681

Both relays and the transistors removed...

41682

Both relays, transistors, and resistors removed....

41683

To de-solder, I found that the copper wicking was more effective. I tried the solder pump but I was more comfortable using the other method. After removing the parts, I tidied up the solder pads and removed the flux with isopropyl alcohol and a Q-tip.

41684

Soldering done. I just have to trim the extra leads off the resistors and transistors and clean up the solder...

41685

Soldering all done and cleaned up...

41686

Here is the top side with the new parts...

41687

Another view....

41688

DLM all buttoned back up with the added 10 amp inline fuse. I didn't integrate the fuse into the module wire as I want it to look stock. I may shorten the leads on the fuse when I install it.

41689

On to testing....

[DMC-81]

Armed with a few 10 amp fuses (Bussman type, with the little hump for a fuse element), I tested the DLM today with both solenoids, and then each solenoid separately, and it blew the fuse. :facepalm:

On a positive note when I disconnected the solenoids, I could hear the relays clicking in my modded DLM and it didn't blow the fuse. :thumbup:

So I guess both solenoids need to be rewound. Who can do this to my exact solenoids (no exchange)?

I'll call Rob Grady tomorrow as I see that he offers this service on an exchange basis.

Cheers,

[David T]

Armed with a few 10 amp fuses (Bussman type, with the little hump for a fuse element), I tested the DLM today with both solenoids, and then each solenoid separately, and it blew the fuse. :facepalm:

On a positive note when I disconnected the solenoids, I could hear the relays clicking in my modded DLM and it didn't blow the fuse. :thumbup:

So I guess both solenoids need to be rewound. Who can do this to my exact solenoids (no exchange)?

I'll call Rob Grady tomorrow as I see that he offers this service on an exchange basis.

Cheers,

The 10 amp fuse will blow if you cycle the locks too many times in a short time. If you use the locks as intended (normal use) the fuse should hold. If it continues to blow you may have to rewind your solenoids. There is a very good How-To to do it yourself. All you need is a roll of fine magnet wire.

[DMC-81]

The 10 amp fuse will blow if you cycle the locks too many times in a short time. If you use the locks as intended (normal use) the fuse should hold. If it continues to blow you may have to rewind your solenoids. There is a very good How-To to do it yourself. All you need is a roll of fine magnet wire.

Thanks David. Yeah, the fuse blew the moment I locked the door for the first time, not on repeated cycles.

[Bitsyncmaster]

Armed with a few 10 amp fuses (Bussman type, with the little hump for a fuse element), I tested the DLM today with both solenoids, and then each solenoid separately, and it blew the fuse. :facepalm:

On a positive note when I disconnected the solenoids, I could hear the relays clicking in my modded DLM and it didn't blow the fuse. :thumbup:

So I guess both solenoids need to be rewound. Who can do this to my exact solenoids (no exchange)?

I'll call Rob Grady tomorrow as I see that he offers this service on an exchange basis.

Cheers,

Sounds like your not getting the timing pulse so the current is only 1 second or less. Do you see both relays operate for just one second?

[DMC-81]

Sounds like your not getting the timing pulse so the current is only 1 second or less. Do you see both relays operate for just one second?

Hi Dave,

With both solenoids unplugged, I hear one relay (I think) click briefly each time I manually lock each door from the inside. I'll take the DLM cover off tonight to see which relay is firing on each door. Is this the intended operation, i.e. when you lock one door, the other door's solenoid locks the other one?

[Bitsyncmaster]

Hi Dave,

With both solenoids unplugged, I hear one relay (I think) click briefly each time I manually lock each door from the inside. I'll take the DLM cover off tonight to see which relay is firing on each door. Is this the intended operation, i.e. when you lock one door, the other door's solenoid locks the other one?

Yes, one relay should click for lock and the other one should click for unlock. Each relay powers both solenoids on one of the coils in each solenoid. I would not believe both of your solenoids have shorted coils requiring rewinding.

Each coil resistance is about 0.80 ohms. So you drive about 15 amps into each solenoid. With your one fuse located in the common supply, your driving both solenoids for a total of about 30 amps. With my testing of fuses I pretty sure if your relay time is one second, that will blow the 10 amp fuse. But I would think with one solenoid disconnected, the 15 amps of current should not blow that 10 amp fuse in one second. That is why I'm thinking something is wrong with your door lock ECU.

I had the lockzilla unit which ran a pulse of about 0.100 seconds. So I'm not really sure how long the OEM unit runs the pulse.

[DMC-81]

Testing part 2: I took the cover off the DLM and manually locked and unlocked the doors with the solenoids disconnected again, and when I unlocked each door, the relay on the left in the picture clicked. The other relay clicked when I locked each door. ( I found that I had to keep both doors in sync to make the relays click... which made sense to me as they are slaved to each other). I verified that both rocker switches fired the relays in both directions, and I didn't blow a fuse.

That would tell me that my switches / DLM should work, right?

41711

Then, I tested the lock coil and the unlock coil on each solenoid with a 12V battery charger.... unplugged from the DLM, but installed in the car.

The unlock coil fired in both solenoids but the lock coil was shorted in both units. I know now what happened to the locks. It must have been a "mild short" as the points on the old relays were not fused together, and the casings of the solenoids had no sign of cooking.

So, I figure that I need to have the solenoids re-wound. Maybe I'll try my hand at this as the How-To seems DeLorean easy. :p

[Bitsyncmaster]

I have a couple solenoids that I removed to install actuators. There are probably others in your area that have spare solenoids also. Don't know the going rate for them but make me an offer if you can't find them local.

[PJ Grady Inc.]

Testing part 2: I took the cover off the DLM and manually locked and unlocked the doors with the solenoids disconnected again, and when I unlocked each door, the relay on the left in the picture clicked. The other relay clicked when I locked each door. ( I found that I had to keep both doors in sync to make the relays click... which made sense to me as they are slaved to each other). I verified that both rocker switches fired the relays in both directions, and I didn't blow a fuse.

That would tell me that my switches / DLM should work, right?

41711

Then, I tested the lock coil and the unlock coil on each solenoid with a 12V battery charger.... unplugged from the DLM, but installed in the car.

The unlock coil fired in both solenoids but the lock coil was shorted in both units. I know now what happened to the locks. It must have been a "mild short" as the points on the old relays were not fused together, and the casings of the solenoids had no sign of cooking.

So, I figure that I need to have the solenoids re-wound. Maybe I'll try my hand at this as the How-To seems DeLorean easy. :p

If you decide not to do your own winding's we have fully reconditioned solenoids that use thicker gauge wire, heat resistant bobbins and soldered grounds. These are stronger and far more reliable than NOS as well as a bit lower in cost. The same assembler has been providing these for about 30 years and I recall only one failure from a frozen stock module in that whole time frame. If you combine it with a Lockzilla module there is a three year warranty which increases to five years if you fill out a survey card within 6 months of buying the kit. Lockzilla kits will be available around the first of May with the remote module and door launcher kit ASAP after the basic kit is released.
Rob

[Morpheus]

Rob,

Is there any word on pricing for the new Lockzilla units? I'm about to order a DLM because my car didn't come with one.

[PJ Grady Inc.]

Rob,

Is there any word on pricing for the new Lockzilla units? I'm about to order a DLM because my car didn't come with one.
I'm am still awaiting final pricing. It won't be much longer.
Rob

[DMC-81]

I was able to get gently used door lock solenoids from Morpheus (Brandon), and I installed them today. Thanks Brandon!

Here is my shorted driver side original.
41784

Here are the replacement solenoids. I just had to use one of my ground wires.
41785

Here is the replacement driver's side solenoid installed. I also cleaned and replaced the black duct tape protection on the door behind the unit.

41786

Here is the shorted passenger side original solenoid.

41789

Here is the new passenger side solenoid with replaced black duct tape door protection.

41787

Here is the installed DLM with the "Elvis" modification which includes new relays, reduced stand by power consumption and an inline 10 amp fuse.

41790

The result is that my power door locks work now!!! :elmo1:

I was able to keep an updated original system for less than $50. :woot:

Also, I bought the parts to rewind my original solenoids for $22. I'll attempt that later and post my results.

41791

Thanks to everyone for your help as you made this possible. Go DMCTalk!!!

[Morpheus]

That's awesome, Dana! I'm glad those solenoids worked for you!

[DMC-81]

Just an update on my modded DLM system, I recently discovered that the 10 amp inline fuse will work while the car is not running, but when I start the car, and move either door lock rocker switch, it will lock once, but immediately blow the fuse in the process. :hmm: It also blew the fuse during repeated unlock/lock cycles when the car was off. (I saw that David T advised that this would happen on repeated cycles).

I checked the connections, whether the locks were binding, etc, and everything checked out. I was thinking that my fuse is possibly underrated. So I tried a 15 amp fuse. That worked beautifully, both when the car is running and when it is not. It also worked during repeated cycles. No more fuses blown.

So my questions are: Has anyone run into this same thing? What would cause this? Would continuing to use the 15 amp fuse not be advisable?

In any case, I'll carefully evaluate the performance over several days of tests.

42120

[David T]

Check the system voltage when the car is running.

[Elvis]

Hi Dana,

with experience from over 10 years and ~50 updated modules, I can tell you that if the 10A fuse burns, the solenoids are bad.

You repaired/replaced one - but the other one is connected to it in parallel. If one burned because the original relay was stuck,
then the other solenoid saw the same energy and must be burned inside, too.


BTW - as you came this far by yourself - do you want to install a remote, too ?
PM me if you are interested.

Have fun,
Elvis & 6548

[Bitsyncmaster]

The timing pulse is determined by a few things. The large capacitor value and the relay resistance, relay dropout voltage. Since you replaced the relays, I'm guessing you are getting a longer pulse than what the standard parts gave.

So it may be your solenoid is bad or your modifications made the pulse time to long.

FYI:
The old LockZilla used 70 amp relays and pretty much the same circuit as the OEM unit but it's timing pulse was very short because of the different relays. It did not matter with solenoids but it was to short to use the actuators.

[David T]

Hi Dana,

with experience from over 10 years and ~50 updated modules, I can tell you that if the 10A fuse burns, the solenoids are bad.

You repaired/replaced one - but the other one is connected to it in parallel. If one burned because the original relay was stuck,
then the other solenoid saw the same energy and must be burned inside, too.


BTW - as you came this far by yourself - do you want to install a remote, too ?
PM me if you are interested.

Have fun,
Elvis & 6548

I agree but that doesn't explain why the fuse doesn't blow unless the motor is running. The other solenoid is probably partially shorted anyway and should be replaced/rewound.

[Elvis]

Battery with engine off: 12.6V

Voltage with running engine : 14.4V

P = U²/R ; P = U * I

R ~ 0.8 Ohm

P @ 12.6V = 200W -> ~16A

P @ 14.4V = 260W -> ~18A

And that's just for one GOOD Solenoid !
So the fuse has to withstand current peaks of ~30A with engine off and ~35A with engine running.
Now imagine the solenoid has less than 0.8 Ohm because it has several shorts inside the winding,
of course the current will go up.

Lot's of theory. Just believe me, a regular red 10A car fuse will not burn when the solenoids are OK.
Others didn't believe me, too, but after they rewinded the coils the fuse stayed alive forever.


Oh wait - the original module has a zener-diode installed that usually is burned as well.
This diode is useless, a bad design, it was meant as protection but instead they all burn as the
needed resistor is missing.
DO NOT REPLACE THAT DIODE ! If you replaced it - this could also be a reason why the fuse burns.
Just cut it out and leave it away.

P.S. - none of the door lock units out there can fix burned solenoids !!!
But the 10A fuse will protect the solenoids, they will never burn again.
And as it has no plastic gears - it should be much more reliable than an actuator.

hope this helps :-)

[DMC-81]

Thanks everyone for the information!

Just to clarify, I replaced both solenoids and tested them before connecting them. There was no obvious shorts, and they didn't blow the 10 amp fuse while the car was not running. However, I'll do some more precise testing...voltage with the car running and not, and I'll measure the resistance on both coils in both solenoids and report back.

I'm hoping for the best because the system works awesome now. :dunno:

One other thing I noticed is that the unlock / lock action works but is weaker when the car is not running, but the action seems stronger with the car running... like any other car's locks. I guess Elvis's solenoid amperage calculation above explains that.

Cheers.

[David T]

Thanks everyone for the information!

Just to clarify, I replaced both solenoids and tested them before connecting them. There was no obvious shorts, and they didn't blow the 10 amp fuse while the car was not running. However, I'll do some more precise testing...voltage with the car running and not, and I'll measure the resistance on both coils in both solenoids and report back.

I'm hoping for the best because the system works awesome now. :dunno:

One other thing I noticed is that the unlock / lock action works but is weaker when the car is not running, but the action seems stronger with the car running... like any other car's locks. I guess Elvis's solenoid amperage calculation above explains that.

Cheers.

Elvis's calculations make a big assumption about the car's running voltage. If the voltage regulator is not working and the voltage gets higher the situatio0n gets even worse! Bottom line, you probably should replace/rewind both solenoids if one is burnt because the other is very likely burnt too. For the short term there is no danger using the 15 amp fast-blow fuse. It is a whole lot better than waiting for the breaker to pop! BTW unless you measure impedance you will not be able to tell with an ohmmeter if a solenoid is shorted.

[Bitsyncmaster]

Elvis's calculations make a big assumption about the car's running voltage. If the voltage regulator is not working and the voltage gets higher the situatio0n gets even worse! Bottom line, you probably should replace/rewind both solenoids if one is burnt because the other is very likely burnt too. For the short term there is no danger using the 15 amp fast-blow fuse. It is a whole lot better than waiting for the breaker to pop! BTW unless you measure impedance you will not be able to tell with an ohmmeter if a solenoid is shorted.

Impedance has nothing to do with the solenoids operation in our car. The DC resistance is what you want but most meters won't be able to read these low values with much accuracy.

Your depending on the power pulse time to be so short as not to blow the 10 amp fuse even though your drawing about 30 amps. I still think the modifications done to the door lock unit made the timing a little longer and that is causing the fuse to blow. You would need to test on an oscilloscope to check the timing.

[David T]

Impedance has nothing to do with the solenoids operation in our car. The DC resistance is what you want but most meters won't be able to read these low values with much accuracy.

Your depending on the power pulse time to be so short as not to blow the 10 amp fuse even though your drawing about 30 amps. I still think the modifications done to the door lock unit made the timing a little longer and that is causing the fuse to blow. You would need to test on an oscilloscope to check the timing.

Maybe impedance has nothing to do with Deloreans BUT it is an accurate way to see if a solenoid has shorted turns inside, something an ohmmeter can't do. Bottom line here, the other solenoid most likely has shorted turns inside casing the 10 amp fuse to blow.

[DMC-81]

Hi again,

Here are the results of my testing:

- voltage with car not running = 12.67 V
- voltage with car running = 14.14 V

Looks within range?

- resistance values of the solenoids:

I used a fairly new multimeter, and tested it's resistance measurement calibration with a 9.1K ohm 5% resistor. The meter read 9.11 on the 20K range setting, and the value with the leads shorted was 0.00.

So, for my test, I set the range selector to 200 ohm. With the leads shorted, the value was 1.5. For the solenoid test, the values a bit fluctuated but settled down to these values during 3 attempts.

Installed solenoids
Driver side: red/pink wire 1.9 ohm, red/gray wire 2.0 ohm
Passenger side: red/pink wire 1.9 ohm, red/gray wire 1.9 ohm

Old solenoids
Driver side: red/pink wire 2.4 ohm, red/gray wire 1.8 ohm
Passenger side: red/pink wire 2.4 ohm, red/gray wire 2.4 ohm

Then, I tested all 4 solenoids again on a 6 amp battery charger by briefly touching the red lead on the appropriate red wire connector while the black wire was grounded to the case.

- old solenoids: only the lock coil (red/gray wire?) was shorted on the driver unit. The red lead wanted to stick to the bullet connector. I previously thought that the lock coil on both old solenoids was bad, but it is only this one. The other three coils worked without much sparking on touching the lead to the connector.

- installed units: the lock and unlock coils worked on both units after a bit of a spark.

A couple questions. In measuring the net resistance, I assume that you need to subtract the 1.5 value of the leads being shorted? If so, that would give .4 ohm on 3 coils of the installed solenoids, and .9 ohm on 3 coils of my old solenoids. Is that right?

Depending on the veracity of my resistance tests, it would seem that my installed solenoids are working, but have half the required resistance. Maybe that is why they work, but blow the 10 amp fuse. What are your thoughts?

I'm leaning toward rewinding my original solenoids ( I was going to do that anyway) and seeing if they work under the 10 amp fuse, before I button back up the inside trim on the doors.

Thanks again.

[David T]

With the leads shorted together you should read 0 ohms. Subtracting any value you do read would be correct but the meter should have zeroed out. You cannot directly relate resistance readings to impedance and resistance cannot, by itself, determine if you have shorted turns. Once you open the solenoids it will be obvious what happened. Since you are blowing the 10 amp fuse it is safe to assume one or both solenoids has burnt. No need to overthink this, you need to rewind the solenoids. It isn't all that hard to do.

[Bitsyncmaster]

It's really hard to get low resistance readings using a multimeter. You need have the connections bolted down or correct pins making the connections. Yes you would need to subtract the reading with the meter leads shorted. It seems like you have a bad meter lead if your reading 1.5 ohms. Normally you read 0.1 ohms with good meter leads.

What I do to get accurate resistance readings is attach the unit onto a bench power supply and set it to drive 1.00 amps into the load. Then you use your multimeter to read the voltage right at the pins to the load. That will remove any voltage drop errors of the test leads.

I just tested one of my good solenoids and the result was 0.82 ohms. Yes the DC resistance is going to tell you if some of the coils are shorted which would result in more current than normal.

So if your voltage to the solenoids was 12 volts, each solenoid would draw 14.6 amps. But at these high currents the wiring can drop quite a bit of voltage. So your depending on the current draw on that 10 amp fuse to be on for a very short time so as not to have the fuse blow with your 20 to 30 amps load. I don't have a stock door lock ECU to measure the timing of it for you. I remember my LockZilla ECU was very short at about 0.1 seconds when I was using that ECU

[DMC-81]

Thanks all for the replies. So, today I started rewinding my original solenoids, starting with the drivers side - the one that had the known short.

(Thanks to Dave Stragland for posting his instructions.)

I used the tip of the bench vise jaws to bend the casing back. I had to bend all the rim back to release the "top hat" back cover - no short cuts here! I then used a nail punch in the hole and a pick on the side to wiggle the cover off. It is also held in by the rubber grommets, so I had to wiggle and pry gently to get the cover off.
43133

Here it is disassembled. The good thing is that there is very little corrosion. This one had the known short in the lock circuit (the one with the red and gray wire). I can already see the burning through the masking tape...
43134

As I unwrapped the tape, it became more obvious. The inner layer of tape was melted to the magnet wire.
43137

I unwinded the magnet wire, and there were 6 layers as the online instructions said. The inner layers had the red cover burned off the wire. Plus, the last layer was melted to the plastic bobbin. It disintegrated in the process, and was slightly stuck to the brass tube.
43138

:banghead:

Question: Where can I buy those heat resistant bobbins that Rob Grady mentioned? Are they common or should I call him?

Thanks,

[Elvis]

The solenoids do not get hot - during regular use !!!!!!


They only get hot when the relays are sticking - and therefore - the 10A fuse is needed to prevent the wires from overheating.

You can use 2-3 layers of tape to replace the plastic, done this ~15 years ago for 2 cars.

BTW - might be interesting for the Germans or even European neighbours - a guy here made a rewinding machine from LEGO
and offers to repair them. If interested - PM me and I'll get you in touch with him.

[DMC-81]

PM sent. Thanks.

Yeah, this burned coil was exactly why my DLM was unplugged when I got the car. I found the root cause! :smile:

Although I have a functioning replacement pair of solenoids, I think if I rebuild my original ones to new spec, they would match my restored and upgraded DLM, and hopefully provide many years of worry-free service.

[DMC-81]

Just an update on the solenoids. I was able to get new, heat-resistant bobbins from Rob Grady. Thanks Rob!

I got enough to do my 2 sets of solenoids. So I continued my efforts to rebuild my original pair today.

44006

Here is the new bobbin (white) next to the old one (black). The new ones are very similar and exactly the same size.
44007

I MacGuyver'ed a winding spool using a 4" mini paint roller and used coat hanger wire to make a crank. Simple, but effective. Here is the first row going on oriented per Dave Stragand's instructions.
44009

1 row on. I needed to keep an appropriate amount of tension in the wire and tighten the rows every 2-3 turns to keep it nice and neat.

44011

3 rows on...

44012

And so on, until I got all 4 coils completed. The roll of magnet wire that I got was enough to do them all, with a little bit to spare.

44014

I'll assemble the first solenoid tomorrow.

[Bitsyncmaster]

Nice re-wind work. Reminds me of winding transformers when I was a kid.

[DMC-81]

Nice re-wind work. Reminds me of winding transformers when I was a kid.

Thanks Dave! It was tedious but rewarding. :)

[Elvis]

Good job and thanks for the pics :-)

[DMC-81]

Good job and thanks for the pics :-)

Thanks Elvis! I thought I'd finish them today, but it decided to re-install my radio /console instead. So the rest of the solenoid work will have to wait for another weekend. :wrenchin:

[DMC-81]

Hi there,

I finished re-building both door locks today. Here was the basic process...

Most metal parts wet sanded with 600 and or 1000 grit sandpaper.
44149

Routing and fastening the ground wires in the copper washer...
44150

Ground washer leads soldered.
44151

Power wires crimped and heat shielded. I scraped the red coating off the magnet wire at the crimp with a razor blade...
44152

Power wires oriented and taped..
44153

Assembly ready to be re-inserted into the case...
44154

Cartridge assembly being re-inserted...
44155

I discovered that the root cause of both solenoids being shorted was by water laying in this crease (where the pencil is pointing), and then running down the back and into the inside of the case. To mitigate in the future, I applied some clear RTV silicone in the indicated crease and in the case crease..
44156

Both solenoids that my car was born with re-built and ready to install in the car.
44157

The result... SUCCESS!!! They both worked and the 10 amp fuse on my modded DLM didn't blow either when the car was running or not.

:elmo1: :elmo1: :elmo1:

For those interested, I included step by step photos and comments in my Electrical album on my profile.

Thanks to all who helped me modify and repair my OEM door lock system!!

[Elvis]

Good job, but the water didn't do anything to the coils.

The reason is and stays the relays.
Especially the original BOSCH relays - they stick together because of the high current and not so good driving circuit.

With the replacements I use I have not had any problems anymore.

[DMC-81]

Good job, but the water didn't do anything to the coils.

The reason is and stays the relays.
Especially the original BOSCH relays - they stick together because of the high current and not so good driving circuit.

With the replacements I use I have not had any problems anymore.

Just checking in on this OEM door lock modification and refurbishment thread. Can't believe it's been almost 7 years, but I'm happy to report that the system has worked flawlessly ever since.

Also, I didn't see this last post, so I'll respond for posterity:

Actually, in my case it was indeed water intrusion that caused the burning in the solenoid. I know this because there was evidence by way of water staining in the inside bottom of the cylinder case where water pooled, and a trace where the water came in through the case seam. In addition, my relays were in pristine condition and passed testing, so much so that I saved them as spares.

Over the years since I did this project, the car was caught in torrential Florida rain a few times, and thankfully the silicone RTV seam I added prevented a recurrence.

[mhanch]

Digging up an old thread -

I just did the Resistors and Transistors on my lock module (Relays look really good. )

and the issue I am having is that only the Lock sire works properly. If i put power tom the Unlock side, it doesn't want to fire. Once in a while if I tap it repeatedly it fires, but then won't fire again for several tries.

Any ideas? i'm using 1/4 Watt resistors, and the Transistors from Elvis' doc.

[Bitsyncmaster]

Digging up an old thread -

I just did the Resistors and Transistors on my lock module (Relays look really good. )

and the issue I am having is that only the Lock sire works properly. If i put power tom the Unlock side, it doesn't want to fire. Once in a while if I tap it repeatedly it fires, but then won't fire again for several tries.

Any ideas? i'm using 1/4 Watt resistors, and the Transistors from Elvis' doc.

Probably your switches in the doors need adjustment. Those are the switches that tell DLM if doors are locked or not.

[mhanch]

I?m testing on the bench. Module worked fine in the car before the update. Wondering if maybe one of the new components could be bad out of the box?


Sent from my iPhone using Tapatalk

[Elvis]

Just checking in on this OEM door lock modification and refurbishment thread. Can't believe it's been almost 7 years, but I'm happy to report that the system has worked flawlessly ever since.

Also, I didn't see this last post, so I'll respond for posterity:

Actually, in my case it was indeed water intrusion that caused the burning in the solenoid. I know this because there was evidence by way of water staining in the inside bottom of the cylinder case where water pooled, and a trace where the water came in through the case seam. In addition, my relays were in pristine condition and passed testing, so much so that I saved them as spares.

Over the years since I did this project, the car was caught in torrential Florida rain a few times, and thankfully the silicone RTV seam I added prevented a recurrence.


I say it was not the water, but hey - it works fine now.

The original relays are not good, the material of the points is not good.
The replacement relays that I use have a better point material, never had to replace
them even after almost 20 years in my car and many updated modules.

[Elvis]

I?m testing on the bench. Module worked fine in the car before the update. Wondering if maybe one of the new components could be bad out of the box?


Sent from my iPhone using Tapatalk

Did you replace the relays ?
The replacements I suggest sometimes touch the plastic housing an won't switch correctly.
Try it without the housing if it works fine. If yes - I have a suggestion / solution.

[DMC-81]

I say it was not the water, but hey - it works fine now.

The original relays are not good, the material of the points is not good.
The replacement relays that I use have a better point material, never had to replace
them even after almost 20 years in my car and many updated modules.

It's OK. We can agree to disagree. As I posted, there was evidence of water intrusion in both solenoids and the resulting shorting in the bottom portions of the magnet coils in the area where the water pooled. In contrast, the original relays tested just fine. I even kept them as spares.

I'm sure there are DLMs where the relays failed, but mine wasn't one of them

[David T]

While it is possible for the solenoids to be damaged by water, that is not how most of them get damaged. Most get damaged when the contacts on the relays get welded together and too much current goes through the solenoids for too long shorting the windings in the solenoids. The contacts get welded together because the relays are not designed to carry that much current and nothing was included in the design to prevent arcing when the circuit is opened. Over time the arcing causes the contacts to weld themselves together. As for water damage, the holes in the bottom edge of the doors have to get plugged up and the door fills with water. That's a LOT of water! I have seen that on cars that were left outside for a LONG time, not cars that get used. Once you open the door all that water will run out.

[mhanch]

Did you replace the relays ?
The replacements I suggest sometimes touch the plastic housing an won't switch correctly.
Try it without the housing if it works fine. If yes - I have a suggestion / solution.

I eventually got one of Dave's units to replace the whole thing - but thanks for asking!