Where to search for the diode? // Interior light does not light up when opening door

[larsmhh]

Hi!
I am really glad that I found this forum with nice and helpful people.
Time goes by and my winter restauration is still not done although it is already march...
I was able to get along with the restauration of the electrics on my DeLorean VIN#1550.
David Mc Keens "Dome Light Module" arrived in Germany after 3 month of shipping!!! Wow, that was "express logistics".
The installation was no problem, also if there is not much space in the relay and fuse compartment.
It works fine, but - as it already did before I installed Davids module - it is only controlled from the RH door switch.
The LH door switch works great (I know this, because it controlls the three lights in the left door the way it should) but does neither communicate with the "door ajay" warning light in the instrument cluster, nor with the "Dome Light Module".
I tried to route the appropriate wires in the wireing schematic and came to one point.
I think, one wire lost its contact to a diode what would explain the working door lights and the loss on corresondence with the "Dome Light Module".
Here is a zoom of section I/J 4/5 on the map with a red mark on the diode I am thinking of...
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I would very much like to ask you if you think the same as I do or if you have any other ideas where to search for the problem.

But where to search for this diode? In the schematics it is just "there" but it could be nearly everywhere in the car. Maybe someone had the same problem before and can tell about his search...!?

Thank you very much and best wishes,

Lars :)

[Christian Dietrich]

I believe that diode is located in the drivers door.

Sent from my SM-N960U using Tapatalk

[David T]

Refer to the Parts Manual section 3-7-3 ref #'s 13 & 14.

[Bitsyncmaster]

The three dome door diodes are in the harness by the drivers right foot.

[WHO1DMC]

http://dmctalk.org/showthread.php?4574-Interior-lights-amp-door-ajar-light-issues&highlight=Door+light

This might help.

[Christian Dietrich]

The three dome door diodes are in the harness by the drivers right foot.Ahhh, didn't think i was right. Lol

Sent from my SM-N960U using Tapatalk

[larsmhh]

Hi!
Thank you very much for your multiple answers, links and information. I was on further education yesterday so I looked for the diodes this morning... and took a photo.
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I measured all three diodes (black, red and blue) with my multimeter and all had a reading of about 0,5 (Volt) and in the other direction infinetely, so the three diodes are working.
I cheked all crimped plugs and all but one looked original and like new. The one that was re-crimped is the plug on the blue diode (purple/white) on the right side of the diode, but the contact is good. But now I know that someone has already been working here. Unfortunately nearly everything the PO did/tried was "not good" in quality so I was always happier to find something not working but original than not working and tinkered...

So my hope is now, that the PO maybe connected either the diode(s) the wrong way or confused the cables on the diodes (or both).
I would be very happy if you could check this with your documentation. I labeled the diodes and cables here:
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THANK YOU VERY MUCH!!!
Best wishes and have a nice sunday,

Lars

[Jonathan]

Those diode connections look about the same as the ones on my own car.

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Could you take a photo or two of the wires connecting to the backside of the door plunger switch on your driver's door? Perhaps you switched up those power wires with the ones that go to the door ajar light and buzzer? It might explain why those door lights get power but are not in sync with the other interior lights.

[larsmhh]

Hi Jonathan!
I agree, the cables and diodes look the same...
Here is a photo of the door plunger switch. Maybe you can find a mistake in this harness?
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I would not expect a mistake there, because the upper switch turns the three door lights on and off as it should.
But maybe they can also be connected on another way to work...!?
Thank you very much,

kind regards,

Lars. :welcome:

[Bitsyncmaster]

My bet is the diode connections has a bad one. Try pulling and wiggling the diode wires as the door is open and see if the dome light comes on. Those crimps with two wires in one terminal seem to go bad.

[WHO1DMC]

Did you check the bulb in the dash?

[Jonathan]

Those door plunger wires look ok to me.

Perhaps it is as simple as a poor connection on one of those diodes, as Dave suggested?

Maybe something else to confirm quickly is what you are seeing with the other interior lights. So you're saying that both the dome lights will work with the passenger door opening and closing? Such that with both doors closed, and all interior lights off, when you open only the passenger door, both dome lights come on?

And if you try again with both doors closed and all lights off, opening of just the driver's door doesn't turn those dome lights on? But it does turn the three door lights on when you do this?

You have your dome lights working with the tip forward or tip backward feature, so that one direction the light comes on and the other direction it only comes on with the door(s) open? There are a few different ways those dome lights can be wired and still get them to work more or less.

[larsmhh]

Hi Jonathan!


Those door plunger wires look ok to me.
Perhaps it is as simple as a poor connection on one of those diodes, as Dave suggested?

I will check this in the evening and will report about the results!



Maybe something else to confirm quickly is what you are seeing with the other interior lights. So you're saying that both the dome lights will work with the passenger door opening and closing? Such that with both doors closed, and all interior lights off, when you open only the passenger door, both dome lights come on?

Yes, that is correct!



And if you try again with both doors closed and all lights off, opening of just the driver's door doesn't turn those dome lights on? But it does turn the three door lights on when you do this?


YES, that is 100% my situation.



You have your dome lights working with the tip forward or tip backward feature, so that one direction the light comes on and the other direction it only comes on with the door(s) open?


Yes, it seems that it are bothe the original ones. I will check the cabling in the evening, too.



There are a few different ways those dome lights can be wired and still get them to work more or less.

Fingers crossed, I still have a little hope for a simple "poor connection".

Best wishes, Lars.

[David T]

On the driver's side there are two switches. There are two groups of two wires taped together. You MUST keep each group of wires separate, ie, one set of taped wires go to one switch and the other set of taped wires to the other. Do NOT "cross" them. One switch is for the lights and the other is for the buzzer. It doesn't matter which switch is which just don't cross the wires. Check that when the dome lights are "flat they are off and will not go on, in one position that one is always on and in the other it goes on and off with the door opening. Check each light. Switching the wires around can make strange things happen.

[larsmhh]

Hi guys, I did find the culprit!
As David suggested...


My bet is the diode connections has a bad one. Try pulling and wiggling the diode wires as the door is open and see if the dome light comes on. Those crimps with two wires in one terminal seem to go bad.

...I checked the terminals, wires and diodes again this evening.

And it was a cold solder joint in the red diode housing. When I checked the diodes before, I did not stress the contacts. Today I did and found out, that the lights go on, if I touch the cables from/to the red diode housing. Distorting the cables did let me first think of the terminal(s), but it was the inner solder joint in the housing. I could not see it, but it was easily measurable with the multimeter.
I then openend the diode housing (pressed the black plastic with the terminals out to one side).
The black platic is a hollow tube, in which a tiny 1N4006 diode was soldered to the metal terminals. I did not see any cold solder joint, but after resoldering the multimeter told me that it did work.
After refitting into the harness IT IS WORKING NOW!!! And the light is brighter and not flickering in detail as it did before.

So let me say: THANK YOU VERY MUCH to all of you, who tried to help!

Best wishes,

Lars :grouphugg:

[WHO1DMC]

wunderbar!

[David T]

Now on to the lamp delay. One problem down and X more to go!