Here's what happens in old cars:
- Old contacts get oxidized and corrode slightly
- This corrosion results in increased resistance at the contact
- Increased resistance = heat at the contact
- Then run significant current through the contact and you quickly get thermal run away where more heat generates more resistance, and then more heat, ...
- End result, melted contact that gets so hot it melts any surrounding plastic!

Solution - clean the contacts if possible. But doing this to all contacts is just impossible. The other solution is to properly fuse circuits as already pointed out.
And the very best is install relays that limit the amount of current through the head light switch and the hi-lo beam stick switch. The relay contact can also corrode but those relays are very cheap compared to the stock switches.

So could simply cleaning the headlight switch contacts restore function? Or is it once you have a melt down like I encountered you are looking at a new switch?

Thanks!

Help!! Headlight switch Failure?
 

The relay kit is used to remove almost all of the current that the stock headlight system runs through the main headlight switch, the turn signal hi/low switch contacts and through the lights.

The only current the switches see after installing the relays is what is required to activate the coils. (Much lower)

The lamps in the circuit are fused, but the switches aren't!
As was designed by Porsche.

Mine only lets the smoke out when I leave the lights on and turn the car off. The 1st position on the switch for running lights does not work right, but when I pull for headlights, they work fine, as long as I turn the lights off before I shut the car down.

http://tapatalk.imageshack.com/v2/14...970d298af7.jpg

Hello,

My headlight went out last night on the highway and when I pulled the switch I found one without a wire connected.

Could the wire have pulled back into my dash? I can't seem to locate it. I believe this is for the high/low beam flash.


81' 911sc - Weekend Project Car
09 GTR - Race Car

Also I do smell a burning smell coming from the switch so I'll probably order a new one tonight....


81' 911sc - Weekend Project Car
09 GTR - Race Car

And, please don't forget the 3A dash light fuse.

I shall, thanks for the idea!


81' 911sc - Weekend Project Car
09 GTR - Race Car

gtrp,

While you have your headlight switch out, can you compare the wiring configuration from my '86 against your SC's wiring?
I am wondering if they are the same.

14 Wires that go into the '86 headlight switch

Turn signal stalk harness
White/black -> 56 (White is the main wire color, black is the stripe color)
Grey/black -> 58L (inside)
Grey/red -> 58R (inside)
Red/white -> 75

Plug Prong harness
Grey/black -> 58L (outside)
Grey/red -> 58R (outside)
Grey solid -> 58 (between 56 & 30)
Grey/white -> N
White/green -> 57
Black/blue -> 58a

Electrical tape wrapped harness
Red/white -> 75
Red solid -> 30
Blue/black & Black/blue -> 58a