Need help with headlamp wires

[2stroke]

Need help identifying what these two wires do. I have not been able to use my headlamps for a while, because every time I would turn them on, it would start to pour smoke out from that area. So today I pulled out the switch and thes wires were melted to some others. I unhooked these two which seem to be connected to each other, and it seem that all functions with the lights now work fine. Can anybody tell me what these are? It appears to be black with a blue stripe, and it comes out of a harness with two big red wires. Maybe from the ignition switch?

[timmy2]

Black/Blue wires are to all the gauge lamps. This is where the in line fuse is recommended to be installed.

[2stroke]

All of my gauge lights still work with those wires disconnected.

[timmy2]

If you look at your photo it is not the only set of Black/Blue wires to the light switch.
I was on my phone and did not look closely. But on my PC I can see the Black/red and the Black/blue wires.
Most people have the wires to the instrument lamps burn up, you had the other set melt...

So, that must be the branch that goes to the ashtray and heater/ventilation control lamps.
The Black with red stripe wire is the feed to the hazard lamp light.

All branch out from terminal 58a of the switch on the '78 schematic diagram found here:
Pelican Parts - Porsche 911 Parts Listings & Diagrams

Print it and tape it together. Look for E20 rheostat on the print. Follow the colored wires.
Those melted wires are part of the main dash harness that connects to the devices I mentioned.

[targa80]

This picture is from my 80SC when I was stripping out the wiring.




The wire with the black/blue and black/red connect to terminal 58a on the light switch. the black/blue wire provides 12volts to the fresh air control assembly lights and the heater control assembly light. The black/red wire connects from terminal 58a on the light switch to a resistor that supplies a lowered voltage to the bulb in the hazard flasher. When the light switch is pulled to the parking light position the fresh air, heater and hazard switch would illuminate along with the instrument back lights. There are other black/blue wires on the light switch that supplies 12 volts to the ashtray and to the instrument backlights.

Since your black/blue wire is fried and has melted the black/red wires then your issue is with the black/blue wiring to your fresh air/heater lights. Those wires supplies three bulbs that illuminate the fresh air control and one light on the heater control. My best guess would be it is possible that the wiring might be pinched against the fresh air hand levers causing a short or you have a broken bulb causing a short. Since I have had the wiring and fresh air assembly out and have reinstalled them both I can see how a short can occur if the wiring is not routed or secured properly in that area.

This is the circuit on the 81SC but should function for your use.

[2stroke]

Thanks guys, as can see the switch is melted too. I have a new one coming, than I will try and figure out how to handle the burnt wires

[timmy2]

2 pics from the 78 Schematic. Same as your car. Different for later year cars.

L15 and L16 are the heater control lamps. L21 is the ashtray lamp. the other blue/black branch is to the gauge lamps.
Hazard lamp wiring is in second picture (connects up top actually)