Blue with black wire behind the dash

[AlKidd]

I decided to trouble shoot my lack of a parking brake light today. Found that the power wire to the socket was broken so with a fix to that and an adjustment at the lever, all is good there. However in removing the light assembly from the dash, I found a small gage blue / black wire that had gotten very hot at some point as most of the insulation appears melted. It looks like the same color wire that goes to the gauges. I was doing this by feel (through the clock hole) but it heads towards the glove box area. I have a fog light switch, with no fog lights, and the lighter over there. The lighter does not work but its my understanding that it should be retrofitted with a modern socket. Can anyone ID what the blue / black wire does and thoughts on what would cook a section of it? There is a connection of some sort roughly behind the parking brake light that someone wrapped in duct tape.
TY
Al

[john walker's workshop]

Often, the dash light loom shorts and burns due to the grounding of the hood light wiring.

[Stevepro]

Hi, As John has suggested the small blue black wire is most likely the loom which powers all of the dash (gauges) lights and the ash tray light. A short somewhere, maybe behind the dash, has probably caused the insulation on the loom to melt. I have had this issue myself.

If you carefully pop all of the gauges out of the dash (all wiring still attached) you should be able to systematically disconnect and remove the complete blue/black loom. There is an insulated spade connector on one end of this loom which plugs into a connection in the main loom. Once all of the individual connections to gauges etc have been removed, you can unplug the spade connector and remove the blue black loom complete. If too damaged, use as a pattern to make a new loom complete or repair the damaged bits of the existing loom. Not as hard as it sounds. Good luck with that. Cheers, Stevepro

[pocketscience]

And put a fuse on that line when you re-assemble..

[Classic 911]

Following


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[Hotshot]

Black Blue are normally lights. Vent / blower / gauges, etc, things with lights. I’ve seen a rouge light un mated to the blower fan icon a bunch. Ashtray light is white normally. There is one lights that’s blue black vs black blue on the vent panel. I think it’s the blower one.

I have spent way to much time looking at 86 wiring diagrams. Lol

[AlKidd]

Thanks all. I agree it definitely looks like a light wire and I did see where I could remove the loom from behind the gauges but does anyone have an idea what would be off toward the right side of the dash? Theres a glove box light (that works), the lighter socket and fog light switch. Not much else over there. Trunk light works. I really dont want to pull the heater to get in there.

[FrankM_]

Apart form the gauge lights, I have the following on this circuit : 4 lights in the heater/blower controls (the 'fan light' only works if the fan is switched on position, ie I or higher) plus the harzard light switch internal light and the central locking light in the center console and if you have option M533 (alarm I think), it also provides power for the 'sign light' whatever that is (I don't have the factory alarm).

As others have said : do put an inline fuse (I used 3.5A) between the light switch 'output' of the rheostat (58a) and the three black-blue wires that provide the power to all these interior lights.

[timmy2]

Best part is, it is different for different years.
Knowing what year you are looking at might help.

[93nav]

According to his profile it is a 1983, called 'Cabo", so cabriolet??? Not sure what years they started making those.

[rothaus]

A short in the instrument light wire can damage the light switch, so installing a fuse can protect the switch.

Take a look: