Drivers door plunger, lights won't come on even if I short the connection.

[Jeff K]

My drivers door plunger lights (door and dome lights) won't come on even if I short the connection. The passenger side works fine. (door lights and dome lights)

Any suggestions?

Thanks
Jeff

[Rich]

Bad diode. There are 3 inline diodes bundled behind the center console. The one for the right door is probably bad.

It's one of the 3 Item 14's on this parts list: LINK: http://store.delorean.com/c-350-3-7-3-main-harness.aspx (http://store.delorean.com/c-350-3-7-3-main-harness.aspx)

The Door & Interior Lighting circuit diagram in this post shows how each of the 2 door diodes are arranged in the circuit: LINK: All-Wiring-Schematics (http://dmctalk.org/showthread.php?40-All-Wiring-Schematics)

[Jeff K]

Bad diode. There are 3 inline diodes bundled behind the center console. The one for the right door is probably bad.

It's one of the 3 Item 14's on this parts list: http://store.delorean.com/c-350-3-7-3-main-harness.aspx

Awesome, thanks. Is this something I can get at an electronics store or is it a DMC custom part, a one amp diode?

[Ron]

It's not going to be a bad diode for the door lights, power to them comes directly off of fuse 12 and then straight to ground via the switch... Could be a bad connection there tho.

Start by checking for 12V (+) on the Purple/Blue wire and that black wire goes to ground.

[Rich]

A generic diode with same rating/performance can surely be found, but it might have solid conductor leads, not the spade lugs you want. You could also spend more time looking for a generic than you want, given that it's a $9 + shipping/handling part....

When two of mine went bad I bought a complete set of 3 at DMCH and they have lasted >10 years.

Having the spade lug connectors potted in there and with OEM connectors solidly on both sides gives some piece of mind in terms of keeping the 12V safely insulated as intended.

[Rich]

It's not going to be a bad diode for the door lights, power to them comes directly off of fuse 12 and then straight to ground via the switch... Could be a bad connection there tho.

Start by checking for 12V (+) on the Purple/Blue wire and that black wire goes to ground.

Ron is correct. I did not pick up that your door lights are also out. The diodes are only for the interiors. As to his last suggestion, yes, check the ground, as in run a continuity check to the ground wire connection.

Sorry for the false diagnosis.

[Ron]

Also, that schematic is missing the Purple wire from the fuse to the Front Interior Lamp (which goes on to the Glove Box Lamp).
I thought I mentioned this in the thread a long time ago, but don't see it...I'll try to edit it.
Should be like this-
17777


EDIT: The corrected version is now at the bottom of the post (click to enlarge it).

[congerz83]

Bad diode. There are 3 inline diodes bundled behind the center console. The one for the right door is probably bad.

It's one of the 3 Item 14's on this parts list: LINK: http://store.delorean.com/c-350-3-7-3-main-harness.aspx (http://store.delorean.com/c-350-3-7-3-main-harness.aspx)

The Door & Interior Lighting circuit diagram in this post shows how each of the 2 door diodes are arranged in the circuit: LINK: All-Wiring-Schematics (http://dmctalk.org/showthread.php?40-All-Wiring-Schematics)

Can this bad diode keep the lights from turning OFF?

[Ron]

No.

The two diodes that are connected to the switches keep opposite side door lights from from coming on when you open one door. Good diodes let current flow in only one direction. So, the way it is wired, if one diode allows both directions ("shorted", internally), the lights on the closed door will come on too -- If it doesn't allow either direction ("open"), opening a door would not trigger the interior lamp delay unit...
The 3rd diode prevents the interior delay unit from grounding the Door Ajar light and turning it on while grounding the interior lights to turn them on (if the light switch is in that mode). If this diode is shorted, the Door Ajar Lamp comes on with the interior lights, even after the door are shut -- If the diode is open, the interior lamp delay unit will never be triggered.

Start trouble shooting by, checking your switches (unplug the black wire(s), not being pushed far enough by the door, ...), borrowing a delay unit, check for one of the Pink striped wires shorted to ground...

[Jeff K]

Thanks for all the input. It was a disconnected ground wire. All good now!

[aipri]

Thanks for all the input. It was a disconnected ground wire. All good now!

Where was the ground? In the door? I have the same issue, passenger door lights work when door is open, drivers side does not.

[Jonathan]

Where was the ground? In the door? I have the same issue, passenger door lights work when door is open, drivers side does not.

Do you know how things look on the other side of that plunger, Anthony? It'll require you to sort of crawl at least up to your neck into the footwell, but you should be able to see the backside of those plungers. There are two plungers on the drivers side, so it complicates it a bit more than the passenger side, and potentially a connector or two got crossed over on to the wrong post. Can you see wiring colours while you're looking in there. You should see some purple ones...

EDIT: take a picture or two if that makes it easier... not quite as hard to stick your camera in there as your head :)

Does your door buzzer go off, btw, when you open the drivers door? Or the door ajar light on the cluster, does it go on and off with the drivers door?

[DMCMW Dave]

Does your door buzzer go off, btw, when you open the drivers door? Or the door ajar light on the cluster, does it go on and off with the drivers door?

Door ajar light is powered by ignition so it only goes on with the key on and the door open. Triggered (via yet another diode) by the same switch as the door lights.

I have no idea why they gave up on diodes and added an entire second switch for the key buzzer, but they did. Probably a different section of the engineering department.

[aipri]

Ok so I took a look behind the plungers, two connectors are disconnected, just want to make sure the right connectors are in the right spots. Here is a picture, when I connect the bare connector (without the black piece on it) to the open spot on the top plunger, the lights come on. Is that the correct spot or is just grounding to metal? If that is right I guess the other connector goes in the other open spot?

21358

[Tillsy]

Ok so I took a look behind the plungers, two connectors are disconnected, just want to make sure the right connectors are in the right spots. Here is a picture, when I connect the bare connector (without the black piece on it) to the open spot on the top plunger, the lights come on. Is that the correct spot or is just grounding to metal? If that is right I guess the other connector goes in the other open spot?

21358

One of the plungers needs the purple/blue and the purple/white - that triggers the buzzer, does nothing more so you can leave it disconnected.

The other needs purple/blue and the black - that triggers the lights.

[Bitsyncmaster]

You will have to experiment to find which purple/blue wire gets paired with the black wire.

[Ron]

The "bare" one is for the lights....

[aipri]

Thanks guys! Got it working, maybe the PO just disconnected it for a show or something because they were afraid of the battery getting drained with the door open. Good day today as I also charged my R12, no more sweating in the August heat!

[Jonathan]

...maybe the PO just disconnected it for a show or something because they were afraid of the battery getting drained with the door open.

That's definitely possible, Anthony. Also if your door alignment is reasonably good and the plungers don't get engaged. It's not unheard of for you to close your door and not realize the plunger didn't stick in far enough to turn the lights off. You can fix that with a $2 pack of what they call "vacuum caps" at your auto/hardware store. Just to give the head of the plunger more meat for the door to press on. Or see about switching out to LEDs in those doors and then it is not normally going to be a concern.

[aipri]

Thanks Jonathan. I definitely want to switch to LEDs, and I know there are guides on here to do so. I've been researching so many fixes at once though I haven't had time to dig into it yet haha