Manfred

My driver's side door light no longer comes on when the doors are open. The switch works as the other interior lights come on when the driver's door is opened. The light does work when put in the always on position.

I measured voltage across the hot lead (red) and the ground (brown) and get 12.5V.

I'm getting 0.6V from the switched lead (brown striped) to the ground.

I'm guessing I have a broken wire in the door from the cyclic bending caused by opening/closing the door. Before I tear apart my door, any other ideas?

As an aside: I have two hot leads going to the light (two red wires twisted together and plugging into the harness) and two switched leads (brown striped) twisted together going into the harness. Is this correct? Why would there be a need for two leads?

Dan

Franks928s

hey dan - sorry I missed you at SITM. There's some threads out here on the interior lights...I'll look to see if I have any book marked. IIRC, I think the fixtures are always hot and its the ground that closes the circuit for them to work. I may be wrong on that so..ill search for some threads.

Frank

joejoe

bulb bad? Wiring sounds o.k., at least my '86.5 is that way (and my 944's)

Mrmerlin

the other red lead goes to the rear of the door edge for the warning light thats pressen into the edge of the door same goes for the switched ground.
if your getting voltage to the light housing then you may just need a bulb. Its also possibe the the rear bulb is all corroded and filled with water pry the rear bulb out of the door edge and inspect the connections up and down should get the rear rubber cover through the door. use some silicone sealant on the harness as it passes through the rubber cover to keep out water when you refit the light housing disconnect the battery first as this is a hot wire and its easy to ground it . then you have to replace the fuse

Manfred

The bulb is working as the light works in the switched on position but not when the door opens (but the other interior lights come on when the door is opened so the switch is working). I've actually been using the VW light upgrade for some time without problems. I can touch the red wire to one end of the bulb and the ground to the other and the bulb lights up. If I touch the switched lead to one end and the ground to the other I get nothing (with the door open of course).

Mrmerlin

Ahh OK so you have a broken wire. Do you get continuity from the switched wire at the light to the pin switch wire?? if not then its
probably in the door loom take the door panel off and investigate

WallyP

The "switched lead" should be brown/red stripe, and is a switched ground, not a switched power wire.

Red should always be hooked to one end of the bulb. The switch on the light switches between three conditions:
OFF - No ground connection.
ON - Connected to brown wire.
AUTO - Connected to brown/red wire, which is grounded by the door switch.

Check these connections on the light unit.

The brown/red wire should be grounded when a door or the hatch is open.

Manfred

Ahh! Thanks for that Wally. Didn't think of a switched ground. I'm at work but will investigate tonight.

Good idea to narrow down the problem area. One question though--currently my pin switch is working fine as judging by the fact that the other lights come on when the door is opened. I've heard that switch can be temperamental--should I leave the switch alone and just take off the door panel or is it a relatively easy thing to delicately take the pin switch out and get the wires at the back of it?

Alan

Two wires crimped into each terminal is not unusual as part of daisy chained connections.

What is most likely is that the connections to the light module is incorrectly plugged in.

Many many cars are like this.. Folks take out the lights then realize they have no idea what plugs back into into what (these terminal are not well marked and are all interchangeable).

Red goes to the direct bulb connection
Brown/White goes to the switched connection
Brown goes to the frame (grounds seperately to the chassis except for the doors).

On the VW units - there is no frame - both Brown/White and Brown go to the switch.

If the direct bulb connection is swapped to Brown and the Red & Brown/White connect to the switch the the unit can be manually switched but does not respond to the door switching - I believe this is what you have (So simply swap the Red & Brown wire connections!)

Alan

Manfred

Thanks Wally and Alan. You guys had it right. Since I was assuming the brown/stripe was a switched lead and not a switched ground I had wired the harness incorrectly. In essence I had it configured so that when in the switched position I had two grounds. Now the only problem is trying to extricate the wire terminals from the harness without the extraction tool so I can do it correctly. Glad I didn't tear apart my door looking for a broken wire that wasn't broken.

The long story is that I had my car in the shop to have the clutch looked at and the mechanic decided to fix my door handle without asking me if I wanted it done (which wasn't broken as far as I could tell). He said he's worked on so many 928s he can tell by the way the handle feels that it's about to break. I guess I'm normally after them to do while you are at it stuff that I didn't argue. Anyway, in taking apart the door he un-did my light and said he wasn't sure how I had it wired so just left the wires hanging out for me to re-install the light. When I first put in the VW light I didn't know what wire terminals to use at the time so I stuck the bare wires in the harness and used electrical tape to make secure them--he didn't want to put it back together without terminals on the wires. Anyway, I decided to take his advice and got the correct terminals but then screwed up on the re-wiring....

Mrmerlin

This last bit of information should have been posted in the first post so to give more back round info on what was fixed last.
Glad you figured things out