Weird electrical leaks

[aludden]

I just changed all my bulbs to LEDs (yeah!) and since they require so little power, they brought a couple of issues to the surface:
1. The stop lights work fine, but they don't totally turn off-they dim. I checked and sure enough there is about 6V at the connector all the time. I pulled all the fuses, and that residual power is still there!
2. When I turn the lights on at the headlight switch (both positions) it makes the turn signal lights come dimly on (and the dash indicator as well). The blinkers still work fine at full power. Pulling the bulb out of the front turn signal receptacle makes the dash and rear go off. The front receptacle is OK and the wires are not shorting there. Pulling the red firewall plug for the rear lights still leaves the dash on (I had my fascia out).

So, two similar problems. I suspected this before, because my battery always runs down if I don't disconnect it (more than the radio would pull, and I don't have the door lock module plugged in). I put in a regular bulb and you can see it barely glow, so it's not the LEDs.

Any suggestions of things to try?
Thanks!
Alex

[Kevin]

I pulled all the fuses, and that residual power is still there!

Now that's strange. I'll start with the stop lights for now. I'd be interested to see if there is power coming from the ground side of the fuse socket while it is pulled (fuse #18 ). If so, I would have to guess there is a short somewhere. To clarify, we're talking about your stop lamps only and not your tail lamps? They're two different circuits, but it sounds like it may be your tail lamp circuit if the turn signal and side markers are affected too. Or, maybe both circuits!

[DMCTek]

I just changed all my bulbs to LEDs (yeah!) and since they require so little power, they brought a couple of issues to the surface:
1. The stop lights work fine, but they don't totally turn off-they dim. I checked and sure enough there is about 6V at the connector all the time. I pulled all the fuses, and that residual power is still there!
2. When I turn the lights on at the headlight switch (both positions) it makes the turn signal lights come dimly on (and the dash indicator as well). The blinkers still work fine at full power. Pulling the bulb out of the front turn signal receptacle makes the dash and rear go off. The front receptacle is OK and the wires are not shorting there. Pulling the red firewall plug for the rear lights still leaves the dash on (I had my fascia out).

So, two similar problems. I suspected this before, because my battery always runs down if I don't disconnect it (more than the radio would pull, and I don't have the door lock module plugged in). I put in a regular bulb and you can see it barely glow, so it's not the LEDs.

Any suggestions of things to try?
Thanks!
Alex

Sounds like you have the wrong bulb in the front park / signal socket. This is a two filament bulb if you replace it with a single filament it can back feed through the turn signal circuit. Make sure this is a double filament bulb.

What happens with the front signal bulbs out?

[aludden]

Now that's strange. I'll start with the stop lights for now. I'd be interested to see if there is power coming from the ground side of the fuse socket while it is pulled (fuse #18 ). If so, I would have to guess there is a short somewhere. To clarify, we're talking about your stop lamps only and not your tail lamps? They're two different circuits, but it sounds like it may be your tail lamp circuit if the turn signal and side markers are affected too. Or, maybe both circuits!

I checked fuse 18 (spare) and both sides are zero. I also checked fuse 8 (in case that's what you meant) and one side has zero, the other has 0.01 I also checked fuse 2 and it also has zero and 0.01 except on the opposite side. I don't know which is the ground side. And yes, I'm talking about the stop lights, not the running lights.

[aludden]

Sounds like you have the wrong bulb in the front park / signal socket. This is a two filament bulb if you replace it with a single filament it can back feed through the turn signal circuit. Make sure this is a double filament bulb.

What happens with the front signal bulbs out?

I know it's an 1157 two-pin. Pulling the LED turns off the dashboard turn signal light and the tail turn signal light. Putting back the old 1157 bulb (as opposed to LED) does the same as the LED - ie turns on the dash and tail turn signals.

[DMCTek]

Sounds like you have a short back feeding the circuit.

The only other thing that stands out to me is the firewall plug for the rear lights is black not red? If unplugging this harness keeps the dash lamp on this helps isolate your search.

[aludden]

Sounds like you have a short back feeding the circuit.

The only other thing that stands out to me is the firewall plug for the rear lights is black not red? If unplugging this harness keeps the dash lamp on this helps isolate your search.

I just went to check and you're right, it's the black plug. When I wrote red above I was at the computer and mis-remembered the color. Unplugging that still leaves the dash light on.

[aludden]

I checked fuse 18 (spare) and both sides are zero. I also checked fuse 8 (in case that's what you meant) and one side has zero, the other has 0.01 I also checked fuse 2 and it also has zero and 0.01 except on the opposite side. I don't know which is the ground side. And yes, I'm talking about the stop lights, not the running lights.

I just looked at the wiring diagrams and I see why you said to check fuse 18. However, the cover of the fuse box says fuse 18 is Spare, and if I pull that fuse my brake lights still work.

I will have to look tomorrow and see if maybe that fuse was bypassed (my melted ones are) or maybe the circuit changed at some point?

[Bitsyncmaster]

I bet the PO tried to wire up the side lights to blink. The brake lights are just a simple on off switch (at the brake pedal). So there must be some PO mod on those also.

[aludden]

I bet the PO tried to wire up the side lights to blink. The brake lights are just a simple on off switch (at the brake pedal). So there must be some PO mod on those also.

Hmmm... good points. I guess I need to pull the headlights out to look at the wiring back there?

[Ron]

The stop light circuit is the simple, so I would chase the problem with it down first...you might get lucky and find the whole problem.

+1 on a bad marker light mod.
...Did you happen to check if the front turn signal sockets have a good ground while both bulbs were removed?

[DMCTek]

I had a chance to think about this some more today at work with a diagram. I believe you have lost a ground in your tail lamp circuit. Most likely original boards. The circuit travels through the riveted bulb sockets which loosen over time.

Pull the boards and twist them while plugged in. This will usually cause the ground to come and go. You can try and repair the loose rivets with a small nut and bolt. The best fix is to replace the boards entirely. Also check the boards plug for loose / corroded wire.

FYI: Early cars like yours do not use Fuse #18. The brake lamps are tied to the ignition switch (no brake lamps with key off). Easy check to be certain if you have the early wiring: Do your brake lamps light with the key off?

[aludden]

Thank you! It;s not easy to see under the fuse box, but I don't think I have wires going to fuse 18. I will check the boards - yes they are original.
Meanwhile, I looked at the brake pedal switch and there is definitely some funkiness there. There are three wires coming from the harness: one green/purple which I believe is the cold brake wire, but it has 3V on it, which I guess is what is causing the brake lights to be on. The other two are green and joined together at the plug and have 0 V. However, they are not being used. Instead, there is a loose green wire which goes up behind the black metal plate, so I can't see where it goes (PO added ?). This has 12.4V and is feeding the brake lights, which do work with the ignition off. I guess the PO didn't like the fact that the brakes didn't work with the ignition off.

To top it off, there is a cruise control which taps onto all these wires. I pulled the fuse in the cruise controller box, but the brake lights were still on. There is one wire from it connected to the green/purple wire, and I did not disconnect it. I guess power could be coming from there.

I will be pulling the dash out soon, and that will make it a lot easier to see all the wires rather than hanging upside down!

I will check the boards. I just had my fascia painted and the connectors got painted :bash: I cleaned them as best as I could. But, I suspect this problem has been going on for quite a while before that.

I will also see if there is a good ground at the front lights, Ron.

Thanks!
Alex

7451

[jmettee]

Alex,
I'd say your cruise control is a likely culprit! That 3V on your green w/ purple is highly suspect - as this is the wire running from the switch back to the brake lights. It should be 0V.

Attached below is a pic from 2075, pretty close to your VIN. I also have the 2 green into the connector that is not attached to anything.

When I use the black on the inertia switch as my ground reference, I have 0.0V at both the unused connector & the green w/ purple wire. The single green attached to the brake switch had 12.1V. All measurements are with ignition off.

According to the wiring schematic on my garage wall, the wires both into & out of the brake switch should be green with purple stripe, but that appears to not be the case on our cars.

Hope this helps.

[aludden]

Alex,
I'd say your cruise control is a likely culprit! That 3V on your green w/ purple is highly suspect - as this is the wire running from the switch back to the brake lights. It should be 0V.
[...]


Oh, good! The only difference in the picture is yours is much cleaner than mine :-)
And I have those pesky cruise control wires. I almost pulled the whole cruise control out, except that I like cruise control, but I never liked the one I have in the D. So I'm of two minds about it. But I will disconnect the wire to see if that solves the problem. If so, then I may have to pull out the cruise after all.

Thanks!
Alex

[aludden]

Well, I disconnected the cruise control wire and sure enough, the problem with the tail lights went away. It's weird because I had pulled the fuse that was in the cruise control box and that didn't change things. I guess I will be removing the cruise control altogether.

I cleaned the ground at the radiator bracket, and checked the sockets and they had a good ground. So I went back and put in the original light bulbs and the turn signal problem goes away. So there must be something wrong with the LEDs. They are 1157s, with two contacts, but somehow they must be shorting the two lines inside. I looked at the socket contacts, and they are lined up properly so they should not be causing a problem. I guess I will call the LED people to see what they say.

Thanks for all your help!
Alex

[aludden]

Still trying to figure out the blinker issue...

Problem is when I put 1157 LEDs in front, and turn the headlight switch to first or second position, the turn signal light in dash and on tail light comes on. This does not happen with the regular bulb. Blinkers still work fine in either case.

I tested my LEDs with a power pack, and the main difference I see is that they work by changing the intensity of the light, instead of turning half off like a regular bulb. In other words, the bulb has two filaments and one comes on for the lights and the other for the blinkers. In the LEDs, all SMDs are lit up all the time. One contact turns them all really bright, and the other turns them dimmer.

I guess the D does not like this kind of a set up? I assume they also make LEDs that work more like a bulb - ie turn half the SMDs for lights, and all SMDs for blinkers? How do yours work?

I know I was told to check for a "marker light with turn signal" conversion, but I don't see anything different behind the marker lights, and with bulbs my marker lights don't blink anyway. And I haven't had time to remove the headlights to see if there is any custom wiring behind the front lights to do such a conversion.

I took apart the front light sockets, cleaned all contacts, and everything looks good - no shorts.
:dunno:

[Ron]

If everything works correctly with regular bulbs then you can probably forget the mod and bad ground...
(just in case, if you have the mod the ground wire going to the front turn signals will be cut/spliced right behind the socket. Ignore what you read about the mod wire colors as they are different for early vins...)


When you say,:
1. "Problem is when I put 1157 LEDs in front", you're not putting 1157s anywhere in the rear, right?

2. "...and on tail light comes on.", you mean rear turn signals, right?

[aludden]

If everything works correctly with regular bulbs then you can probably forget the mod and bad ground...
(just in case, if you have the mod the ground wire going to the front turn signals will be cut/spliced right behind the socket. Ignore what you read about the mod wire colors as they are different for early vins...)


When you say,:
1. "Problem is when I put 1157 LEDs in front", you're not putting 1157s anywhere in the rear, right?

2. "...and on tail light comes on.", you mean rear turn signals, right?

Hello Ron, thanks for helping! Correct, everything works fine with regular bulbs, and there are no changes to the wiring behind the marker lights.
I am only putting 1157s in the front, and yes I mean the rear turn signal light.

Both LEDs are doing the same thing, even if I swap them. That's why I am asking if this is how all 1157 LEDs work, or just these.

I was wondering if the LEDs were just shorted internally, so if I put my meter on 200k ohms across the two bottom terminals of the LED I get a reading of 0.1 (I don't have a continuity setting on my meter). That's probably the circuitry to make them either bright for turn signal or dim for regular light. Is that enough to cause them to short the two circuits? Both LEDs are the same (GP Thunder) and give the same result.

[Ron]

I can findd the GP thunder for 1157 (dual input) but it looks like a 1156 (one input)
http://www.hid-lights.com/products/led/1157/GP-1157-SMD-18W.htm

Got a link to exact bulb you're using?

[aludden]

"GP Thunder"- got a link link to exact bulb you're using?

http://www.hid-lights.com/products/led/1157/GP-1157-SMD-68A.htm

[Ron]

Do you have access to another vehicle that uses a 1157 bulb to test the LEDs with?
Almost all of the older cars used them...if it fits and has two contacts it should do the trick..

EDIT: Also, If you put a LED in the front on one side and a regular on the other side, does everything on the regular side work correctly.....?

Do hazard lights work correctly with regular bulbs in front?

[aludden]

Do you have access to another vehicle that uses a 1157 bulb to test the LEDs with?
Almost all of the older cars used them...if it fits and has two contacts it should do the trick..

EDIT: Also, If you put a LED in the front on one side and a regular on the other side, does everything on the regular side work correctly.....?

Do hazard lights work correctly with regular bulbs in front?

Hah! We have 3 Mercury Villagers and none of them use an 1157.

However, I think the problem may be in the sockets. I've swapped the bulbs many many times, and a couple of times the regular bulbs did something similar. And now I just did your hazard light test and the regular bulb did cause the tail regular lights to blink dimly just after the turn signal would blink off. And the dimmer filament was blinking up front instead of the bright one. Jiggling the bulb made it all work correctly.

The sockets were heavily corroded (especially the right one) so I cleaned them with a dremel wire brush until shiny. The wires look OK and are not shorting. The LEDs do have a wider oval contact on the bottom instead of the regular bulbs, which are round solder dots. I guess I can grind down the LED contacts to a round point to see if that helps (but then I won't be able to return them if I need to). The ovals only seem to be scratched in the center, so I didn't think that was causing a problem.

Actually, I wouldn't mind replacing the sockets, but DMC only sells the entire front light assembly. Do you know if it is a standard socket, available in auto parts?

[Ron]

Maybe a kind neighbor? A lot of them are extremely easy to get to. ;-)

If a socket is bad and not grounding a bulb, power can run from one input through the filament, to the internal common ground, through the other filament ("backwards") and out the other input, if grounded (This is roughly how the mod for the markers works...and the LEDs won't like all this).

I think the ovals are a good thing...

Yes, the sockets are the same and probably have the correct wire colors for your VIN (Red, Green, Black for passenger side.... ). The only thing is that you have to find ones that mount the same, two ears straight across. There are several that only require partially trimming one ear off, several have spring loaded 'fingers' that allow you to just push them in the hole.
Maybe someone else knows of a exact fit?

EDIT: I just remembered noticing bulbs don't fit in the front sockets very tight...it may be possible to turn them even though the pins on the bulb are backwards if they are also in poor shape...not likely...just a thought.

[aludden]

[...]
If a socket is bad and not grounding a bulb, power can run from one input through the filament, to the internal common ground, through the other filament ("backwards") and out the other input, if grounded (This is roughly how the mod for the markers works...and the LEDs won't like all this).
[...]


That's exactly the kind of thing I am suspecting. I'll have to re-check the sockets, and/or also see if I can find a replacement. Yes, the lamps are pretty loose in the sockets, but I have been making sure to put them in right.

I did check the LEDs with a 12V battery pack. That's how I know that they are dual-intensity. As a matter of fact, they do work better/brighter that way than when I put them in the car. I really don't think the LEDs are bad. I think it's the wiring/ground/sockets.

What do you think of Bill's ground bus, or some other way of enhancing the grounds?

Thanks for your help! I'll look for sockets in the next couple of days.

[Ron]

... What do you think of Bill's ground bus, or some other way of enhancing the grounds?At fIrst thought, 'overkill' comes to mind, but during the project he definitely identified a couple of things that needed improvement, which I would fix if/when a problem arose or was ever in the area...by adding another line (and documenting it). IMO, 99% of ground problems are simply bad connections, mostly due to lack of maintenance/contamination/abuse...

[aludden]

At fIrst thought, 'overkill' comes to mind, but during the project he definitely identified a couple of things that needed improvement, which I would fix if/when a problem arose or was ever in the area...by adding another line (and documenting it). IMO, 99% of ground problems are simply bad connections, mostly due to lack of maintenance/contamination/abuse...

I will be removing the dash and center console, so I figured this would be the time to do something like that. I went ahead and ordered the wire. I did a number of things recently and my voltmeter has seen a significant improvement. I'm not sure if it's any one thing (maybe a loose belt? or a cleaned up ground?) but I welcome the change. I'm also happy I got the LEDs almost done!

[aludden]

So, do I need to remove the headlights in order to disconnect the front turn signal pigtails?

[Ron]

I doubt you can find an aftermarket socket with the correct plug for the harness end, which means you'll have to splice anyway, so all you have to do is remove the two screws in the lens and it all comes right out where you can work on them. Solder the splices and heat shrink them...

[DMCTek]

So, do I need to remove the headlights in order to disconnect the front turn signal pigtails?

No, pull the front grill and you can unplug the pigtail. You have to fish the wire up through to reconnect it but it's not to difficult.

[Ron]

I don't understand why you'd do that to replace a rotten socket???

[aludden]

I don't understand why you'd do that to replace a rotten socket???

Well, the last time I cut a wire I later regretted it because I couldn't find a replacement socket. I wound up having to rebuild the old socket and re-soldering it in. So this time I saw in the manual that this one has a plug and I figured I would unplug it so I can take it to the auto parts place...
Just being conservative.
But you're right, I could just cut it if I can be reasonably certain of finding a replacement.

[Ron]

Ah, I'm with you there...it sounded like you already tried to rework them and nixed the idea...

[aludden]

Ah, I'm with you there...it sounded like you already tried to rework them and nixed the idea...

No, I'm still replacing them if I can. I just have been swamped with work this last week, so I haven't had time to work on the D. Plus, it's been very cold!

[Ron]

LOL... I think I need a translator! I meant nixed the idea of fixing the old sockets not fixing the the lights.

(In case I haven't confused a simple thing enough ;-) ...If you remove the two screws, there is plenty of slack in the wires to work with. If you cut them off there, you can take the lens and socket with you to match up with. The new socket can be spliced in right where you cut the old one off. If for some odd reason you can't find a suitable aftermarket socket (or not fast enough), you can always put it all back original by purchasing an original socket since it comes with what you cut.

I assumed you already had the screws out but, by now, the time difference in the two ways is probably less than the time it took to read all these posts. lol

[aludden]

LOL... I think I need a translator! I meant nixed the idea of fixing the old sockets not fixing the the lights.
[...]


Well, I had cleaned the sockets with a dremel, and wire brushing, etc but I am still having a problem. So, I did go to the auto parts today and just took the front lens. We were able to match one pretty well I think. I will see tomorrow. I'm not too happy about the quality of the socket, but at least it will be new and not rusty. I think the combination of old rusty metal (in spite of the cleaning) and the loose socket is what is causing the problem. I will tell you tomorrow!

[Farrar]

This part...

http://store.delorean.com/p-6898-frt-turnslde-lp-assy.aspx

...comes with the socket/pigtail assembly.

Maybe you can call Houston and see if they will sell you the socket/pigtail assembly without the lens cover.

Just a thought.

Farrar

[aludden]

This part...

http://store.delorean.com/p-6898-frt-turnslde-lp-assy.aspx

...comes with the socket/pigtail assembly.

Maybe you can call Houston and see if they will sell you the socket/pigtail assembly without the lens cover.

Just a thought.

Farrar

Yes, I mentioned before that Houston had it, but I thought it was silly to get the whole assembly when I just need the sockets. But as you said, I could ask...
I've got so many other things going right now (my whole interior is taken apart) that I will get to it one of these days...
Thanks!
Alex

[Farrar]

Alex,

You might be surprised by what you can get just by asking... When I bought my car, its front end sat way too low and I was constantly scraping the sway bar brackets. The springs that were on the car looked like Eibach springs (shiny black paint with the part number in white), but I figured there was no way they could have been correct, so I removed them and put stock springs on the front and kept the rears. I threw the old springs away. Not long after, I saw a note from Houston saying that Eibach had sent them a bad batch of springs and the fronts would sag over time, and they recommended swapping them out. I called up Houston and explained the situation and asked if they had a pair of front Eibach springs that hey could sell me. I was informed they only sell them in sets of four. But after several weeks elapsed, I got a call saying that Eibach had accidentally shipped them one set which consisted of four fronts instead of two fronts and two rears, so they could sell me just the front Eibach springs if I wanted them. James just happened to remember the conversation I had had with him about the springs when he saw that box, so he called me up and sold them to me!

So it just goes to show you that you never know -- if someone over there knows you need a part that otherwise is part of a set, they might happen upon one in some of their work and say "Hey, Alex needs one of these. Let's give him a call." :)

Farrar