Interior Dome Lights Not Working - 87 911

[Rick W]

The interior dome lights in my 1987 911 aren't working. They do not work in any position nor do they come on when either of the doors open. The frunk light, clock and glove box lights all work correctly. I have removed and cleaned/Deoxit the door switches and checked the light bulbs. Occasionally the lights will intermittently come on. I notice a clicking sound behind the dash on the drive's side when I push the driver's side door switch in and out when the lights are intermittent. Could there be an issue with the power window relay? Would appreciate anyone's thoughts or suggestions on where else to look and try. Thanks

[Rick W]

A bit more info. My car is a Japanese market 87 911. Just checked the power windows again and they work with the door open, but not when the door is closed, when the key is not in the ignition. I have searched many of the posts here and understand that the interior dome lights may connect through the power window relay. When the door light switch on both doors are pressed, a clicking sound can be heard behind the fuel gauge in the dash (which is where I understand the power window relay is?). Not sure if that is normal or not. Thanks

[creaturecat]

you try grounding out the dome light fixture?

[Rick W]

Yes, I checked both grounds and both appear to be good (ground to the door switch and ground to the roof). I checked for power and there is no power in the black wire. The fuse powers the clock, radio and the interior lights. The clock is working fine and the fuse checked out fine (radio is removed at the moment). I need the trace where the next downstream connection point is for the power wire so I can test the various sections. Any suggestions as to where I can find the next connection point? Also on the workshop electrical drawing there is reference to NR 45, BEL M650 NR 34/64. Any idea what these refer too? Thanks

[wazzz]

Originally Posted by Rick W

Yes, I checked both grounds and both appear to be good (ground to the door switch and ground to the roof). I checked for power and there is no power in the black wire. The fuse powers the clock, radio and the interior lights. The clock is working fine and the fuse checked out fine (radio is removed at the moment). I need the trace where the next downstream connection point is for the power wire so I can test the various sections. Any suggestions as to where I can find the next connection point? Also on the workshop electrical drawing there is reference to NR 45, BEL M650 NR 34/64. Any idea what these refer too? Thanks

NR something is usually the loom number.
M650 is option ref. for electrical sun roof.
BEL, no idea. It may be some German leftover acronym or abbreviation. Maybe "belag"?

Also, what is your car? Coupé ? If so, sun roof, no sun roof ? Targa ? Cabriolet ?

[Rick W]

It is a coupe. No sunroof.

[Rick W]

I checked again and confirmed there is no power getting to the interior dome light. The wiring diagram shows that there is a connection point where the power wire heading to the interior dome lights branches off to feed the clock, glove box and trunk light. All of the clock, glove box and trunk light are working properly so I am thinking that the power wire issue for the dome lights is at that junction or between that junction and the dome light fixtures. Can anyone give me some guidance as to where these wire connection points are in the car? Behind the dash somewhere? I'll post an image of the wiring diagram showing the connection point I am referencing. Thanks

[Rick W]

[gerakroo]

The interior lights connection has 4 wires attached to a 2 pole connector. 2 x brown-white and 2 x black. One of the brown-white goes to the diode on to the main harness, the other one directly to the left door switch. The first black one (+) to the 8 pole (male) alarm connector near the fusebox. The other black one goes to the small ignition switch buzzer contact. On the other side of the 8 pole (female) connector the black wire goes to your fuse panel, thats where the plus is coming from.

[Rick W]

I think I may have located where the interior lights wiring connection comes into the front trunk by the front trunk light but can't seem to get to the connection. Is there another way the access the wires?

[Rick W]

Still haven't been able to figure out the power issue for my interior dome lights.

Does anyone know where these wiring connections are located in the car? I believe somewhere between these connections is where the power loss is coming from.

Thanks

[Mr. Merk]

I fought one of these recently. I had the gauges out with my hands chasing the harness. Suddenly they started working and have been since! No clue

[Rick W]

That was my next thought too as the clock seems to be in the same wiring circuit as the interior lights. Hoping to find out the location of where the wires connect before pulling out the gauges. Pretty cramped spaces trying to find the various wire connections.

[Rick W]

Still can't figure out why my interior dome lights aren't working. I have checked the bulbs, the ground connections, door switches - all good. I ran a wire direct from the positive terminal of the battery to the power connection on each light and they work on both ground connections. I am pretty sure I found the interior light wiring connection indicated on the orange sticky note on the wiring diagram attached. I traced this wire to where it enters behind the dash and when I move it around I can hear the wire moving around in the roof of the car. I confirmed the ground connection is good on this wire (brown/white wire) but no connectivity through the black power wire. I also ran a wire from the positive battery terminal to the black power wire and neither of the lights powered up. My only thought is that there is an issue at the next wire connection junction (yellow sticky note on the wiring diagram attached) but I cannot locate this. It must be in the window pillars or in the roof somewhere. At this point it looks like the only way to get access to this connection, and to check the continuity to the remaining run of wires is to somehow pull the wires out from the dash location (with string attached to each end so they can be fished back up once the wiring is sorted out). But this sounds like too much work. Not sure if anyone has any further thoughts or ideas.

[Rick W]

[EC900]

For my inoperable dome lights I found that the replacement headliner fabric install was interfering with the body ground, perhaps even some glue. It was just a tiny bit of unnoticeable fabric that was the culprit. Cleaned the area and trimmed 1//8 fabric around the opening where fixture makes body contact.

[Rick W]

Thanks. I'll give that a try.

[Rick W]

Thanks EC900. I pulled the drivers dome light out, wiggled the main wiring harness behind the dash a bit a bit and the dome lights started working. Reassembled and still working good.

Really appreciate your assistance!