figgen

as of late I have been experiencing some odd interior light behavior. The symptoms are as follows:

With all doors shut, all interior lights work on the "always on" setting - Normal
With all doors shut, all interior lights are off on the courtesy setting - Normal

With any door open none of the interior light work on any setting.
Volt meter reading to the red power lead on any light bezel = 0 with any door open.

First blush = fuse is OK, but I'm going to re-check.

So any thought on what would cause the power to go out on the main power lead when doors are open?

John Struthers

Possibilities:
1. As always: check the door pin switches. Rarely, they will look good but the outer shaft might
be worn thru.
2. The pin switch shaft might be sticking = always closed position, shaft should move freely.
3. Service lead to pin switch broken.
4. Swap out that fuse, just for grins. (#23 , I think, should be 8 amp).
Watch out, if you are going to clean/inspect individual courtesy lights as there is no lack
of brown wires. There is a history of fried wiring/contacts at the body of these interior lights.

If you have had the door panels off you might have accidently miswired one or more of these
puppies when you slapped her back together. A lot of lighting issues seem to surface after preventative maintenance, side markers are another candidate for miss-wire issues.
For what its worth...
On Pattycakes my 82' Weissach the hatch light operates independently of the driver/pass. door lights.
Go figure...
Have fun, let us know the outcome, bitte.

Bret928

Check the interior lights themself. I had a similar problem with mine, that turned out to that one of lamps waw miss wired. So unless I had the lights in the off position they'd stay on all the time. Someone must've pulled them at one point or another and put them back together wrong.

If you have a volt meter it's pretty easy to figure out whats going on by popping the lamps out as you would when replacing the bulbs. and leaving the ground connected pull off the two quick disconnects and measure them with the doors open & closed. One should only see voltage when the doors opened and the other should see it all the time. Good luck.

Bill Ball

The red lead is supposed to be constant 12V. I would recheck that since the fact that the lights work at all means 12V is getting to them and the fuse is good.

Does ANYTHING happen when you open the doors?
- Do the red door edge lights illuminate?
- Do you get the chime if the key is in the ignition?

Do the lights come on in the courtesy position if you open the hatch? (This would point to a light delay relay failure)

Easiest explanation is no ground through the door pin circuit, but that doesn't fit with your lack of 12V constant on the red leads. Maybe Brett is onto something with a misswired light, but my rudimentary electrical skills are failing me.

figgen

I checked the lights with ONLY the rear hatch open. Same deal as with the door open. No light operations on courtesy position OR constant power position, so it looks like I'm plagued with no voltage being sent to the red power lead when the doors/hatch is in the open position.

Is it possible the red power lead is grounding out when the doors are open, thus power taking the path of least resistance? I supposed this would blow the fuse though.

The door chime (keys in door open) works as advertised so no problem there.

I'll double check the fuse but if the same fuse is used for constant power on as intermittent power on then it has to be OK because with all doors closed I have power to all lights.

I'll go through each light and see about wiring but none of the wiring has been disturbed for any reason lately. IIRC the red power wire should always have 12 V power and the constant on should always have ground. The brown/white has intermittent ground, specifically when the doors are open the ground is complete to the fact I have no power when the doors are open baffles me. When doors are open is there a relay or something of the sort that changes the 12 source on the red wire for an
85?? I checked my relay diagram and it seems the interior light relay is only used in 86.5, so I don't think it applies.

Bill Ball

If the door chime works and goes off when you close the door, then that verifies that the door pins are working.

So, if you switch a light to always on and pull the red wire, is it 12V? Weird. With the wire still dicsonnected and on the volt meter, move the light switch to courtesy.

This is one for Alan.

Alan

Do all your lights work the same?

Do your door end (red) lights work normally?

Are some of your lights brighter than others?

Try turning all the lights to the center-off mode - do the door end light work correctly then? If yes - try switching each lamp to the door switched mode individually one at a time - which ones work and which do not?

I suspect you have one or more lights wired incorrectly - the red wire (or green in the hatch) should always be to the unswiched end of the fixture - connected direct to the bulb - i suspect one (or several) of yours are connected incorrectly.... if one bulb is notably brighter - take that one out first and investigate...

Alan

figgen

SUCCESS !!!!


John Struthers # 4
While pulling all the light bezels I noted an interesting item. The rear hatch button was not working. I had had this problem before which was previously promptly repaired with a new 5 A fuse.

So after verifying all light wires were as they should be (and they were), I ventured back into the fuse box. previously I had taken a multimeter and by placing it on "continuity = beep" mode I touched both exposed sides of the installed fuses and received a "beep" on all of them. BUT of course the door was open when I conducted this test so I had continuity across the 5 amp fuse but backwards and not across the fuse it's self (through the car body and the open door ground to each side of the fuse). After pulling and visually inspecting the fuse it was obvious it was NFG and a quick replacement had all in order.

Darn I feel stupid.

Thank you for all the suggestions and helping me trace the steps to the cause.

It is interesting to note my 12 volts must come from one circuit for the constant on and another for the courtesy function as when the doors were open I had ZERO volts on the main red power lead to the bezels (assuming the circuit then takes voltage from the rear hatch open circuit - which had the blown fuse) but 12 volts was present once the door was shut - main power circuit fuse OK

Good to know

Bill Ball

This doesn't sound like the way it should be according to wiring diagrams. The 12V comes off a common 30 line that feeds a lot of stuff. Alan?

Anyway, glad things are working.

VehiGAZ

Now that Rich's prob is solved, I'm hijacking this thread to solve my own bizarre-lighting-behavior problem...

All of my interior lights work correctly except for the passenger side door light. It goes on in the always-on position, goes off in the always-off position, and when in the door-on position, it switches off when the door opens and switches on when the door closes. The door chime works, the pin switch works, but the light operates backward in the door-on position. I have not checked it against the operation of the red door end lights.

Any guesses?

Alan

Rich - you still have soime kind of a wiring problem... there is only one real 12v supply the one from the fuse... check the other lights one by one:

brown/white wire (white in the hatch) is the switched ground, Brown is the permanent ground - red (or green in the hatch) is the +12v supply from the fuse...

Also check the delay relay - do you have the right type installed?

I suspect you will find the fuse blows again soon... open the hatch and doors together - fuse still OK?

Alan

Alan

GAZ - check the wiring as above for the door light... also do you have the correct delay relay installed - do you actually get a lighting off-delay? is the relay the right part#?

Alan

VehiGAZ

Thanks for the tip Alan - I will check the wiring. I don't think I have any delay when the door closes - off it goes and that's that. I'll check the interior lights relay p/n.