Smoking light switch scare

[Lyndon302]

68 911.
My light switch is smoking. After initial panic re smoke in my cabin I have traced it to the light switch.
All light work except my dash lights. The reostat is toast and it lights up light a toaster.
I take it power in and then out to my dash lights.
Can I bypass this by bridging the wires. I'm happy to have full brightness on my dash.
Thanks lyndon

[Discseven]

L... If the reo is glowing like a toasted toaster, replacing the light switch would be advised but surely you have already considered this. So to your "bridge" question, yes, the dash lights can be circumvented at the switch. There may be any number of ways to do this. Referencing an '80 light switch that I'm familiar with, there's the first pull on the switch that turns on the running lights. I'd splice into power from that circuit if I wanted dash lights ON at that switch setting. Next pull on the switch turns ON the headlights. If dash lights are wanted ON on that switch setting, I'd splice into power from the headlight circuit. Question is whether a relay should be used for the dash lights when doing such a bypass/bridge---I'm not sure. Having recently delt with my own light switch wire toasting, I have been advised from what I consider relaible sources that a 3 or 5 amp fuse is good to install to protect the dash light circuit.

.

[Tea Tray]

If your rheostat/resistance wire/dimmer wire is glowing then the switch or downstream circuit may have a short to ground. The resistance wire is designed to be in series with the dash lights (which are wired in parallel) and should never normally glow.
Adding a 3 amp fuse is a great idea.

[Lyndon302]

I fused the dash lights a few years ago.
The switch is all crunchy when I rotate it.
I've yet to check the fuse.
Dash lights were on. Fiddled with the dimmer
Then went off and I had smoke.
All I have done is tracked down the source and relieved my loom was the issue.
PS. I have extra fuses everywhere and two emergency battery shut offs.
Lyndon

[Lyndon302]

My question is.
Can I disconnect the rehostat or it hot all the time. I believe it's earthing and thus shorting out.
Dash lights work on first pull as well. Eg Parking lights or only head lights
Dash lights work with IGN off ??

Lyndon

[Lyndon302]

Does anyone have a diagram for each wire.
What I have is to hard to read.
Im seeing if I can modify it or fit a generic one.
It seems to feed the fuel pump and spark plugs.
Lyndon

[7783911]

[Tea Tray]

Dash lights work w/o ignition on. Terminal #30, unfused from battery energizes #58a which goes to the dash lights. Ohming #30 to #58a with the switch pulled to either park or headlight position and turning the dash light dimmer knob makes about a 10 ohm difference.
You can’t disable the dimmer function without taking the switch apart.
In the photo you can see the (likely nichrome) resistance wires (that do the dimming) in the small window. There are two windows.
I wonder if there’s a snowballs chance there is a stray wire poking into the window causing the short.

[fintstone]

https://forums.pelicanparts.com/porsche-911-technical-forum/105819-dash-lighting-fuse-installation.html

[Lyndon302]

Good info.
57 speedo light ?? ( Thought this would be a dash light ) is it IGN 12v

Why two terminals for left and right headlights and Parker's ( battery fed I'm presuming not IGN )

K high beam. Tacho and ash tray ( some more info if possible )

56 high low flashing. I presume battery and feeds the stalk.

Lyndon

[Lyndon302]

That pic supplied is not my switch.
68 911 SWB
Lyndon

[Lyndon302]

[img]http://forums.pelicanparts.com/uploads26/163571645234119030599300619862031635716447.jpg[/img

I think as easy fit. Remove the debris. Cut of 12 supply and hard wire dash to parking lights
Lyndon

[SpyderMike]

Though the newer switch was not your specific year, the circuit designators were consistent over years...the functions were similar.