Electrical Grounding

[Regulus]

Hello again everyone,

Nice to have the forum back, for a couple of months I thought that Delorean ownership had plunged back into the info-vacuum of the 1990s.

Question for everyone; I've been trying to solve a ground problem somewhere in my car since I bought it. The problem is only pronounced when the AC compressor is engaged. To solve this problem, i've re-grounded the battery ground from the frame to the transmission directly. This seemed to help, but didn't solve the problem completely.

Any other tips on re-enforcing the ground on the car's electrical? should I ground the battery directly to the frame and transmission? I already cleaned the engine-to-frame ground strap, plus a raft of other grounds, but can't seem to find the fault.

Any Ideas?

[Bitsyncmaster]

What makes you think you have a ground problem?

The Starter, alternator and AC clutch all require their case have solid grounds. The get the grounds by case contact to the engine or mounts to the engine. You have to make sure there is no paint or corrosion on the metals where they mount to the engine.

[Regulus]

Hi Dave,

This is the same A/C problem I've had for about 3 years now. the electrical is fine until the compressor is energized, or more precisely, until the compressor clutch disengages. that sends a spike thru the system. On my 140amp DMCH alternator, this manifested itself as a 1 second idiot light flash timed with the compressor disengagement. With a 110 amp Pj Grady Alternator, it was generally asymptomatic for about 10 mins, when it then died. the alternator came back for about 2 mins, then froze totally open, sending 18volts plus to the battery! total regulatory failure. I know that regulator hate bad grounds, which leads me to think its a ground fault. i have the 140amp on there now, but have had the regulator of the 110 amp rebuilt. even with the battery grounded directly to the transmission case, i have had no luck.

since it is only the compressor that is problematic, should i look to unmounting, cleaning, then remounting? I just can't see how the compressor would lose ground to the block overtime, its on there pretty good.

Any thoughts?

Thanks

[content22207]

Run a 2 gauge battery cable ground bus from the front of the car to the rear. Tie every single ground junction into the bus. Of course attach the bus directly to the battery. Only costs $20 or $30 and eliminates all electrical anomalies.
1169 1166 1167 1165 1164 1170 1163 1168

Bill Robertson
#5939

[Ron]

Any thoughts?
Like Dave said, it would help to know what makes you think you have a ground problem... It sounds like your battery/alternator may be too weak to handle the demand when the compressor kicks in...stock cooling fans (power hogs) automatically come on at the same time.
You might try connecting one end of a (quality) jumper cable to the battery (-) and connect the other end to suspect ground points while the problem is present while watching for a change in the symptom.

[Regulus]

It sounds like your battery/alternator may be too weak to handle the demand when the compressor kicks in...stock cooling fans (power hogs) automatically come on at the same time.


I replaced my stock fans with Wings-B-Cool fans from DMC NW, all the lights are LED on the car, JOE Cool installed. Basically every amp saving device is on the car. Oh, the battery is a Optima red top, alternators were brand-new when installed.

I do like your idea of running a ground from the battery to the compressor directly. I will definitely try that.

If it's not a ground, why else would the compressor cause such an electrical disturbance when releasing the clutch?

[Ron]

I replaced my stock fans with Wings-B-Cool fans from DMC NW, all the lights are LED on the car, JOE Cool installed. Basically every amp saving device is on the car. Oh, the battery is a Optima red top, alternators were brand-new when installed.

I do like your idea of running a ground from the battery to the compressor directly. I will definitely try that.

If it's not a ground, why else would the compressor cause such an electrical disturbance when releasing the clutch?
I'm confused- You first said 'the problem is only pronounced when the AC compressor is engaged'. Here, when 'releasing the clutch' (or when disengaged). The clutch is relatively low power, so I doubt its the problem.

What kind of "disturbance"??? Depending on what you are looking at it with, you may just be seeing the the results of induction as the field in the coil collapses when it kicks off (along with the fans, relays, and maybe a bad condenser (capacitor)???
Elaborate, from the beginning, what you did to improve it, what exactly improved, what it is doing now. -- Don't worry about too much info. It's easier to ignore than guess the right question to get to "what didn't matter" :wink:

[Regulus]

-- Don't worry about too much info. It's easier to ignore than guess the right question to get to "what didn't matter" :wink:

As far as I can tell, the problem only occurs when the ac compressor disengages. The battery idiot light would come on for about a second when the AC compressor disengaged. eventually, it fried a regulator on an alternator. Another indicator that the problem occurs during AC clutch release is that I fried a Dakota digital clock in my consol when the clutch disengaged (well, on a few cycles the clock flickered on/off, then it died). After a rewired the battery ground off the frame to the transmission, the problem seemed to go away for a few cycles, but cam back after 5-6 on/off cycles. This problem exist even when set to By-level (I understand that that setting also engages the compressor). I've try two separate new alternators, with similar symptoms.

I also tried wiring in a diode inline to the compressor, but i didn't help (it was only a 6 amp diode)

Beyond this, i have no ideas.

Thanks for everyone's help thus far,

Alex.

[Ron]

Ah, I remember the problem somewhat from the old forum now...

You might try this:
Remove the wire feeding the compressor. Then run a fused wire from the battery (+) to a switch and on to the compressor. Now, place all of the controls as when calling for AC and use the switch to engage/disengage the compressor (simulating cycling). If the problem doesn't show up after doing this, say, a dozen times or so (twice what it normally takes for the problem to show up), you have probablly eliminated the compressor.... Be carefull not to run it too long at a time causing the pressure to get too high.

[dmc6960]

all the lights are LED on the car

I would just like to verify that your battery light in the instrument cluster is or is not LED?

It should not be LED.

[Bitsyncmaster]

I'm remember the old post also. From what you describe it does sound like a ground issue. Sounds like your engine block ground is faulty (weak). I would add a second engine block ground.

But if the engine block ground were were bad I would think your starter would have problems. Maybe the left cylinder head has the bad ground.

[Regulus]

I would just like to verify that your battery light in the instrument cluster is or is not LED?

It should not be LED.

Correct, Battery light is incandescent.

[Regulus]

I'm remember the old post also. From what you describe it does sound like a ground issue. Sounds like your engine block ground is faulty (weak). I would add a second engine block ground.

But if the engine block ground were were bad I would think your starter would have problems. Maybe the left cylinder head has the bad ground.

I thought the entire block used the same grounding strap (by the right side of the frame). Do the two engine banks ground separately?

[Bitsyncmaster]

I thought the entire block used the same grounding strap (by the right side of the frame). Do the two engine banks ground separately?

It should only take one ground strap for the whole engine. But yours is an unusual problem. The block depends on all the bolts making the metal all one conductor. The paper gaskets would separate the aluminum.

I did put another ground wire (#4 AWG) on the drivers side like the passenger side OEM strap. I did not have any problems but thought it was a good idea.

[DMC3165]

I have a similar problem lately. I'm not sure if its the same as the OP but when my A/C compressor comes on with the lights on as well the voltage drops way down. The needle hangs just above the high red line. It's not the fans. If the fans come on without the A/C the voltage drop is noticeable but minimal. Could it be a ground issue with the engine or the compressor?

[82DMC12]

I have a similar problem lately. I'm not sure if its the same as the OP but when my A/C compressor comes on with the lights on as well the voltage drops way down. The needle hangs just above the high red line. It's not the fans. If the fans come on without the A/C the voltage drop is noticeable but minimal. Could it be a ground issue with the engine or the compressor?

That sounds more like a weak alternator. Which one do you have? Cleaning all the ground could help but if you have a weak alternator it really should be replaced.

Andy

[Bitsyncmaster]

Does it help when you give it a little gas?

[DMC3165]

That sounds more like a weak alternator. Which one do you have? Cleaning all the ground could help but if you have a weak alternator it really should be replaced.

Andy

It's a Hervey 90 amp I put in last November. Everything is ok while driving or idling without the air on.


Does it help when you give it a little gas?

Yes. If I'm sitting at a light speeding up the motor brings up the voltage.

[Bitsyncmaster]

It's a Hervey 90 amp I put in last November. Everything is ok while driving or idling without the air on.



Yes. If I'm sitting at a light speeding up the motor brings up the voltage.

Do Your idle RPMs hold the same with or without the AC on?

Your alternator may be weak or a bad connection. Try cleaning up the bolts holding the alternator onto the engine.

[DMC3165]

Do Your idle RPMs hold the same with or without the AC on?

Your alternator may be weak or a bad connection. Try cleaning up the bolts holding the alternator onto the engine.

Yes the Rpm are the same at idle. I will check the connections this evening.

[Ashyukun]

Yes the Rpm are the same at idle. I will check the connections this evening.

Check the tension on the alt belt... I've got one of Hervey's higher-amp alts and I'm becoming more convinced that the pulley on it is just ever so slightly too small such that there isn't enough adjustment in the bracket to tension it properly without having extended the slot so I can get more tension and that it slips slightly when the engine is colder or there's a higher load on the alt...

[content22207]

The pulley is more than "ever so slightly" smaller. John's website lists a 90 inch belt "for Special T alternator" and a 95 inch belt "for stock Motorola or Ducy alternator." By using a smaller pulley he spins the alternator faster, increasing power output at any given engine RPM.

Bill Robertson
#5939

[DMC3165]

Yesterday afternoon I went through the entire car. I started with the alternator connections. There was some corrosion but very little. I also pulled off the main ground strap on the engine and cleaned up those contacts again as well. I also unplugged the red wire by the A/C unit and gave those contacts a quick cleaning. In the process I also pulled out every external lightbulb and cleaned up all those contacts as well. Most everything was pretty clean and showed only minimal amounts of oxidation if any at all.

In the end 4 hours later it made absolutely no difference at all. I do notice while driving at night the lights dim for 1/10 of a second with a quick drop and recovery on the volt gauge with the A/C on. This happens about every minute or so which I can only assume is the compressor cycling. So I'm thinking maybe the compressor is going bad? Will it draw heavily on the electrical system when they are starting to go bad?

[Bitsyncmaster]

The compressor clutch draws about 6 to 10 amps. But when the compressor kicks on it also loads the engine so at idle you may see a momentary drop in voltage because of the RPM drop.

My guess is your alternator has weak output power.

[DMC3165]

Someone is offering me a 140 amp DMCH alternator right now. I am hesitant to install such a high output unit in a car that was never designed for 140 amps. What are your opinions on this.

[Bitsyncmaster]

Someone is offering me a 140 amp DMCH alternator right now. I am hesitant to install such a high output unit in a car that was never designed for 140 amps. What are your opinions on this.

What I have heard of some of the high output alternators is they have low output at idle speed. I don't think John even sells them anymore.

[David T]

Alternators cannot put out their full, rated output at idle. Just because you did not find the bad connection does not mean you do not have one. You can use a voltmeter and look for large voltage drops while you are running your A/C. The A/C does a "double whammy" on your car's systems. Not only does it add a very large load onto the idling engine, it adds a LOT of electrical load all at once by using the heater fan, both cooling fans, and the clutch. While you are driving you can actually feel it in the gas pedal when the A/C cycles. You feel the car "pulling back" and slowing down. Start by having the battery load tested and the alternator checked. Then clean ALL of the "big" connections.
David Teitelbaum

[Chris 16409]

What I have heard of some of the high output alternators is they have low output at idle speed. I don't think John even sells them anymore.

I spoke to Toby about this low output at idle problem. He said Dave at DMCMW found a very good alternator shop locally that is making the latest iteration of alternators. Toby said they were designed to have good output at idle. I never had a problem with the Houston unit. I had some bad wiring going to the starter, which I thought was a bad alternator. I bought a D-110 to try and fix the problem, but the starter wires got burned on the exhaust manifold. (SPEC 1 manifolds, be sure you properly route your wires if you install a new exhaust system.) Once the wires were replaced, my battery light problem went away. I did notice that my volt gauge sat higher with Houston's unit.

[David T]

At idle, during periods of very high electrical loads, the battery is supposed to supplement the alternator. Not meant for long periods, more like stopping at a traffic light. Off-idle the alternator should be going fast enough to handle the loads. This works unless you have a chronically under-charged battery. If you use the car infrequently and the battery is never fully charged, the alternator will always be trying to recharge it. This puts an additional heavy strain on the whole electrical system and reduces the life of the battery and alternator. The answer is not a high output alternator. Get a trickle charger like a Battery Tender and if you do not use the car keep the battery fully charged with that so all the alternator has to do is handle the operating loads on the electrical system and not have to always recharge the battery. The only recharging the alternator should have to do to the battery is replace the power that was used up to start the motor. If that is all it has to do it can more easily handle the other loads on the electrical system.
David Teitelbaum

[Ashyukun]

The pulley is more than "ever so slightly" smaller. John's website lists a 90 inch belt "for Special T alternator" and a 95 inch belt "for stock Motorola or Ducy alternator." By using a smaller pulley he spins the alternator faster, increasing power output at any given engine RPM.

Bill Robertson
#5939
*sigh* I wish that were more prominently stated on the site- like in bold with the alts in question that you must use a smaller belt. I wish it didn't require pulling the A/C belt to replace the alt belt. :/

[jawn101]

*sigh* I wish that were more prominently stated on the site- like in bold with the alts in question that you must use a smaller belt. I wish it didn't require pulling the A/C belt to replace the alt belt. :/

I agree completely with that, but when you buy the alternator he does include the right belt... fortunately the A/C belt is pretty easy to remove and re-tension. IMHO the alt belt is much harder to tighten up, and even that is pretty easy if you get the tools just right. Don't worry, you'll get it and you'll be glad you did! My car has never been healthier since I installed the D110.

I also completely rebuilt the wiring in the fuse compartment though - all new fusebox, relay strips, terminals, breakers, fuses, relays, etc... I got another 2 volts on the meter immediately after doing that. Good luck!

[Ashyukun]

I agree completely with that, but when you buy the alternator he does include the right belt... fortunately the A/C belt is pretty easy to remove and re-tension. IMHO the alt belt is much harder to tighten up, and even that is pretty easy if you get the tools just right. Don't worry, you'll get it and you'll be glad you did! My car has never been healthier since I installed the D110.

I also completely rebuilt the wiring in the fuse compartment though - all new fusebox, relay strips, terminals, breakers, fuses, relays, etc... I got another 2 volts on the meter immediately after doing that. Good luck!

Unfortunately, due to how long my car had sat prior to my getting it, my main pulley was really crusty and ate two A/C belts and the included alt belt- and I didn't realize I needed a shorter one and put a normal-length one on after that... had I known, I would have gotten a shorter replacement belt...

[jawn101]

Unfortunately, due to how long my car had sat prior to my getting it, my main pulley was really crusty and ate two A/C belts and the included alt belt- and I didn't realize I needed a shorter one and put a normal-length one on after that... had I known, I would have gotten a shorter replacement belt...

Ah, sorry to hear it. Don't worry, you'll get there! :)

[DMC3165]

Where does the negative battery connection attach to the car? I may be on to something in cleaning all these connections and I'd like to get all of them.

[Chris 16409]

The negative battery connection is located next to the passenger side trailing arm. Specifically, the connection is at one of the bolts for the trailing arm bushing cover plate. Be careful because these bolts are double nutted. If you don't remove the free spinning nut first, you will shear the bolt off. One nut is welded inside the frame which you can't see. The other nut is more accessible, but still a pain to get off.

This would be a good time to install Hervey's new ground cable. You have to remove the original batter ground cable, so you'd be doing this anyway just to clean the terminals.

[DMC3165]

Ok so forget about pulling the ground strap right now. Visually it looks ok with no obvious signs of corrosion and is on there tight.

I did find both my starter connections were loose! Meaning the nuts were only hand tight and the haven't been touched in 13 years! So I cleaned them up and re-attached them. It does seem much better now. Not a wide swing on the volt meter and with all accessories on the gauge drops down halfway between 13 and the high red line so its obviously better then before.

One other thing, there was a small flat connector on the side of the solenoid that was connected to a white wire with a blue stripe...I think. It was badly corroded but salvagable. Just curious, what's it for?

[Bitsyncmaster]

One other thing, there was a small flat connector on the side of the solenoid that was connected to a white wire with a blue stripe...I think. It was badly corroded but salvagable. Just curious, what's it for?

Do you mean blue/yellow on the starter solenoid? Do you have the OEM starter? My OEM starter had ring terminals on all the wires.

[content22207]

However it is connected, that is the resistor grid bypass wire (bypasses half the resistor grid while cranking to increase spark).

Bill Robertson
#5939

[DMC3165]

Do you mean blue/yellow on the starter solenoid? Do you have the OEM starter? My OEM starter had ring terminals on all the wires.

I believe its an OEM starter. My car was a Grady refurb done in 99. Generally everything is like it was when Rob did it back then, including the starter.

[Bitsyncmaster]

I believe its an OEM starter. My car was a Grady refurb done in 99. Generally everything is like it was when Rob did it back then, including the starter.

Like Bill said, that extra wire is for the resistor bypass. You can test if that bypass circuit is working by starting the without the white wire plugged into the resistor block. If it works, your car will start but the engine will stop when you release the key.

[Ashyukun]

I swapped in a 90" belt in my work today, and the voltmeter stayed a lot higher at idle even with the A/C running (which drags my idle down since I have a carb and no kickdown for the A/C at the moment). Still wish I'd known this a year ago... :/

[Regulus]

Hello Everyone,

So I hammered in about 3 separate new ground cables into my Car yesterday. I bridged the A/C Compressor to the block, the block to the frame, and the block to the negative battery cable direct.

Unfortunately, the problem persists as before. The battery light flashes briefly when the A/C Clutch disengages. I feel confident in saying that this is not a ground issue. Which leds to the question, what is causing this electrical spike by the A/C Clutch? Could the internal compressor wiring be faulty?

Thanks,

[content22207]

I swapped in a 90" belt in my work today, and the voltmeter stayed a lot higher at idle even with the A/C running (which drags my idle down since I have a carb and no kickdown for the A/C at the moment).

Curious -- I ran my A/C virtually nonstop for 12 of the past 24 hours, and even at idle compressor load only dropped my RPMs 50 or so (I have witnesses).

Bill Robertson
#5939

[TTait]

I have the same problem as Regulus on one of the two cars.

This car is an automatic, 2.5 year old Houston alternator. Hervey replacement compressor, Hervey fain fail fix, low current fans, original untouched starter...

I concur that it seems to be the compressor turning off - don't think its the fans because the engine should be warm enough to keep them on.

Regulus, your a lot further down the road checking for a solution, anything you want me to check on my end?

Tom

[Bitsyncmaster]

When the AC cycles, the fans cycle at the same time unless you have a fan controller that delays the fans. So maybe it's the fans causing the flashing light and not the compressor clutch.

[Regulus]

When the AC cycles, the fans cycle at the same time unless you have a fan controller that delays the fans. So maybe it's the fans causing the flashing light and not the compressor clutch.

I thought that too, but once I fooled around thinking the problem may have been my Joe Cool. When I three way jumpered the fans, I did it wrong and totally eliminated power to the fans. The light flash problem happened when the compressor kicked off again, this time with no fan at all.

I'm going to put an inline capacitor on the clutch line. Hopefully that evens out the power spike. Right now I'm just looking around for a Capacitor that will take that much amperage.

Thanks

[TTait]

When the AC cycles, the fans cycle at the same time unless you have a fan controller that delays the fans. So maybe it's the fans causing the flashing light and not the compressor clutch.

And I've observed mine happening when the engine is at full operating temperature, so I presume the otterstat is closed and the fans are operating full time anyway. Mind you I'm driving so I can't tell if they are running for sure. I'll confirm it later today here in the garage...

While may car has been off the road for about 6 months, this problem began a year ago when it was still being driven regularly . As soon as I started using the AC yesterday it started again.

I further tested it last night by observing that the light would flash every 30 seconds or so. I then turned off the AC and it absolutely stopped, but the engine temp did not start to come down, so I presume the fans stayed on. Drove about 5 minutes with no ac and no flashes. I then turned the AC back on and after about 20 seconds the first flash occurred again.

[Bitsyncmaster]

I thought that too, but once I fooled around thinking the problem may have been my Joe Cool. When I three way jumpered the fans, I did it wrong and totally eliminated power to the fans. The light flash problem happened when the compressor kicked off again, this time with no fan at all.

I'm going to put an inline capacitor on the clutch line. Hopefully that evens out the power spike. Right now I'm just looking around for a Capacitor that will take that much amperage.

Thanks

The Joe Cool will delay the fans anyway.

Any capacitor will work. Normally it's just to suppress electrical noise by slowing the rise and fall times of the current changing in the inductive load.

Use a capacitor with 25 volts or greater rating. Value of 0.5 to 1.0 uf is best for noise but larger may help with the flashing. I don't think that will fix it but can't hurt to try.

[TTait]

I just went to see if installing my fanzilla would do anything to help, and I realized that my blue relay base has been cut out and the wires taped off. I did not have Johns fain fail installed, just a relay in the fan base...

I think i have a spare relay base, so I'm going to start by wiring a fan fail base back in, and then try the fanzilla...

[TTait]

Okay, I wired in a socket for the missing blue socket. The PO had cut it out and taped brown orange output from the circuit breaker directly to both black/green fan wires. Similar in theory to Johns fan fix jumper, except un-fused.

The new socket isn't blue, nor is the orientation correct for the ground pin at the bottom, but neither fanzilla nor Johns products use that pin, so its installed for now to let me keep testing.

So with a properly working fanzilla and two low amperage fans, the light still comes on intermittently when the compressor shuts off.

I'll try to find and test the diode. Per the updated wiring diagrams hosted on this site that is at the point where the black/orange wire coming out of the fan relay (not fan fail) connects to the pink wire running out to the compressor. I'm guessing that's where the main wiring bundle routes under the fuse box, and then turns to the rear of the car, at the most inboard point of that bundle.

Is there a part number for the diode? I can only find the 1 amp and 3 amp diodes... Is this a 3 amp?

[Bitsyncmaster]

Is there a part number for the diode? I can only find the 1 amp and 3 amp diodes... Is this a 3 amp?

Just use a 3 amp diode to build your own. But you can test yours by swapping it with one used elsewhere.

If the light comes on when it shuts off then I would try a diode from ground to the compressor clutch wire (the bar end of the diode). That will shunt the inductive spike you get when an inductor turns off quickly. I bet that has a better chance of fixing it than a capacitor.

[TTait]

Okay Dave...

Im at Fry's now.

I've got a 1MFD 50volt capacitor, non polarized NPR1M50

and a NTE5131A diode, sound good?

So I tie in the diode with the band (cathode) end on the pink compressor wire and the annode at a good ground... And how do I tie in the capacitor? Its non polarized according to the packaging, but one wire is longer, which I recall denotes something...

What now?

[Bitsyncmaster]

Okay Dave...

Im at Fry's now.

I've got a 1MFD 50volt capacitor, non polarized NPR1M50

and a NTE5131A diode, sound good?

So I tie in the diode with the band (cathode) end on the pink compressor wire and the annode at a good ground... And how do I tie in the capacitor? Its non polarized according to the packaging, but one wire is longer, which I recall denotes something...

What now?

You got it correct. If the capacitor is non-polarized (and it should be for noise reduction) it can be connected either way.

[Farrar]

Dave,

What about a few strategically-placed chokes? Have you tried that?

Farrar

[Bitsyncmaster]

Dave,

What about a few strategically-placed chokes? Have you tried that?

Farrar

A choke filters AC noise but would not do much to fix turning the power on and off. It would also need to carry all the current of the clutch.

[TTait]

Just to have the best chance of success, The capacitor goes in line in the pink wire to the compressor, and the diode goes from this line to ground. Now, should the diode tie to this line on the compressor side of the capacitor, or on the supply side of the capacitor?

Maybe it doesn't matter.

Thanks for you advice on this Dave.

One other question - when I first got my '82 there was a resistor? mounted in a round depression somewhere in the air mix unit. It had a yellow wire I think that was corroded and no longer going anywhere. I was told that it was from the factory and only on some cars, and used to supress electrical noise, and was not really useful... How much of that is true, as I no longer have one and I don't see it anywhere in the parts diagrams?

[Bitsyncmaster]

Just to have the best chance of success, The capacitor goes in line in the pink wire to the compressor, and the diode goes from this line to ground. Now, should the diode tie to this line on the compressor side of the capacitor, or on the supply side of the capacitor?

Maybe it doesn't matter.

Thanks for you advice on this Dave.

One other question - when I first got my '82 there was a resistor? mounted in a round depression somewhere in the air mix unit. It had a yellow wire I think that was corroded and no longer going anywhere. I was told that it was from the factory and only on some cars, and used to suppress electrical noise, and was not really useful... How much of that is true, as I no longer have one and I don't see it anywhere in the parts diagrams?

No, the capacitor is also wired to ground just like the diode.

That part you see on some cars in the mix unit is a capacitor. It does fix a lot of switching noise when installed. My car never had one and I installed the diode and cap and it curred dome light noise (tunning on when engine went to idle). That is the same issue of switching an inductive load (the advance solenoid.)

PS:
My new idle ECU added this capacitor just in case yours was missing.

[Ron]

I was posting a possible solution to the flashing light problem but lost it and a long explanation when it asked me to login....:dead:

Anyway, try changing the diode that goes between the Otterstat and Cooling fan relay.
It is the one with (B)lack-(O)range wires on both ends of it (butted up to one with B-O and Pink on the anode.)
Short explanation is the diode is shorted internally allowing the induced voltage from the AC clutch coil to get to the otterstat and on to the light along the green wire. Problem could be intermittent because it will only do this when the otterstat is hot enough to call for the fans....

?

[content22207]

I was posting a possible solution to the flashing light problem but lost it and a long explanation when it asked me to login....:dead:

The new DMCTalk does that to me too (automatically logs me out after a minute or two). Mozilla does remember the post I was writing, however, and lets me go back and reload it after logging back on to the site.

Bill Robertson
#5939

[sean]

I was posting a possible solution to the flashing light problem but lost it and a long explanation when it asked me to login....:dead:



The new DMCTalk does that to me too (automatically logs me out after a minute or two). Mozilla does remember the post I was writing, however, and lets me go back and reload it after logging back on to the site.

Bill Robertson
#5939

Oh Noes!!!! you guys have a common enemy now :nervous:

[TTait]

I was posting a possible solution to the flashing light problem but lost it and a long explanation when it asked me to login....:dead:

Anyway, try changing the diode that goes between the Otterstat and Cooling fan relay.
It is the one with (B)lack-(O)range wires on both ends of it (butted up to one with B-O and Pink on the anode.)
Short explanation is the diode is shorted internally allowing the induced voltage from the AC clutch coil to get to the otterstat and on to the light along the green wire. Problem could be intermittent because it will only do this when the otterstat is hot enough to call for the fans....

?


Short but sweet - Cool! I'll try that too.

[TTait]

Update - I temporarily installed a capacitor and a diode as outlined several posts above, and the problem seems to have gone away. I failed to follow proper instructions though, as I installed the capacitor and the diode in series to ground, rather than parallel, but it still worked. I can rewire and try parallel soon.

In the meantime, the advice about the diode in the pink wire having failed makes a lot of sense. Rather than waiting for the oem one to arrive from Houston, I just ran out and picked up an NTE569 600V 3amp rectifier/diode. Is this a reasonable replacement for the oem 3 amp diode?

Tom

[Bitsyncmaster]

Update - I temporarily installed a capacitor and a diode as outlined several posts above, and the problem seems to have gone away. I failed to follow proper instructions though, as I installed the capacitor and the diode in series to ground, rather than parallel, but it still worked. I can rewire and try parallel soon.

In the meantime, the advice about the diode in the pink wire having failed makes a lot of sense. Rather than waiting for the oem one to arrive from Houston, I just ran out and picked up an NTE569 600V 3amp rectifier/diode. Is this a reasonable replacement for the oem 3 amp diode?

Tom

Yes that diode will work. Also wiring the cap and diode in series will help reduce some noise but parallel will be better.

[Spittybug]

I was posting a possible solution to the flashing light problem but lost it and a long explanation when it asked me to login....:dead:

Anyway, try changing the diode that goes between the Otterstat and Cooling fan relay.
It is the one with (B)lack-(O)range wires on both ends of it (butted up to one with B-O and Pink on the anode.)
Short explanation is the diode is shorted internally allowing the induced voltage from the AC clutch coil to get to the otterstat and on to the light along the green wire. Problem could be intermittent because it will only do this when the otterstat is hot enough to call for the fans....

Is this diode located in the fuse area or inline woven into the harness in the engine bay?

[Bitsyncmaster]

Is this diode located in the fuse area or inline woven into the harness in the engine bay?

It's in the relay fuse bay. In the harness to the right side of the fuse block. There are three (I think) diodes there.

[Ron]

It's in the relay fuse bay. In the harness to the right side of the fuse block. There are three (I think) diodes there.
+1

[spikeygg]

Run a 2 gauge battery cable ground bus from the front of the car to the rear. Tie every single ground junction into the bus. Of course attach the bus directly to the battery. Only costs $20 or $30 and eliminates all electrical anomalies.
1169 1166 1167 1165 1164 1170 1163 1168

Bill Robertson
#5939

Bill, this was what I've been looking for. I have a question though, what are those cubes that take a bunch of little wires and go to the thick cable? Do you have any pictures or instructions on how to create that junction?

Thanks,
-Greg

[content22207_2]

They are saddle portions of clamp on electric lugs from Lowes:

44166

Cut heat shrink off the OEM junction (leave the soldered connector in place), strip some insulation off the ground bus wire, slide the saddle into place, insert OEM junction into the saddle, tighten the set screw (cut off exposed set screw threads if you're OCD like me), then wrap everything in electrical tape:

44167

BTW: my bus is 4 gauge, not 2 -- don't know what I was thinking.

Bill Robertson
#5939

[content22207_2]

Don't forget to tie the bus directly to the battery:

44168

One of the weak links appears to be the OEM battery to frame wire. Community lore is the terminal loosens with age. It's located right next to the pavement anyway, which is hardly optimal in terms of rust and grime.

Bill Robertson
#5939