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Join Date: Oct 2016
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Light switch smoking!

Hello,

has anyone had a similar problem to this:
When I pull the light switch out, to the first notch for the side lights, it's fine, but when I pull it to the second notch for headlights it starts to smoke! All the wires seem to be correct.

Do you know why it's smoking and how can I stop it?!

Many thanks

Andrew

Old 06-27-2020, 04:18 AM
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The early cars run all current through the headlight switch. This is a good time to install a headlight relay kit. Don’t use the switch until you isolate the problem as replacement HL switches are $$$ and you especially don’t want to risk melting any wires in the harness.
Bill
Old 06-27-2020, 09:14 AM
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Andrew77 hasn't bothered to give us his location, but it probably isn't important if we just follow the smoke and flames.
Old 06-27-2020, 09:48 AM
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ejboyd5 - I think that is rather unnecessary! I had thought this was a friendly forum, but perhaps I was wrong.

It is not case of not being bothered - I just don't know how to do it. However, if someone is asking for help I would suggest sarcasm is not very helpful, and their location is irrelevant, but maybe I am wrong about that too!
Old 06-27-2020, 10:17 AM
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Anyone silly enough to continue to use a "smoking" component deserves nothing better. Remove the headlight switch from the instrument panel and determine what is wrong. Do both headlights illuminate when the switch is pulled to the second detent? Do the high beams come on when activated by the lever on the steering column? What about the turn signals, do they work? The headlight switch in a Porsche (you haven't bothered to give us the year) is a very complex hub of the electrical system that was over stressed from the day it was built. This problem is compounded by 50 years worth of deterioration to the wire insulation and, perhaps, some prior attempts at repair. Some lessen the load placed upon the switch by installing relays to power the headlights Your question is very difficult to answer without a detailed examination of the several circuits that pass through the headlight switch. One of the first things you should do is to install a battery cut-off switch so that when a malfunction occurs you are immediately able to isolate the power source and halt the emergency. Still looking for your location as there might literally be someone right around the corner who would be able to help if this work is beyond you. In any event, do not use the car before you get the problem sorted or you might not have a car.
Old 06-28-2020, 03:26 AM
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EJ
Lets try to maintain civility and adult behavior here. If your ego demands you treat others in a demeaning manner keep in mind that this hobby represents the toy department of life and should recognize a shared enjoyment of Porsches at all levels of experience.
Andrew has asked several legitimate questions which have produced responses without lecturing or a need to be perceived as some sort of expert. I am here to share whatever knowledge I have with others - nothing more, nothing less.
Finally, please learn to end your posts with your actual name.
Bill
Old 06-28-2020, 08:41 AM
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Thank you, Bill. I was just about to reply, but you have saved me that job!

I am a novice at restoring any car, let alone a 1968 912, having imported the car to the UK (Derbyshire) from the US in good faith three years ago. I was assured it was a runner and solid. So, being faced with a non running car, with a completely rotten floor, I was faced with the choice of selling it straight on, or getting on with learning how to fix it. It has been a long process, and I have learnt a lot - much of which is due to the help provided through this forum, for which am very grateful.

After three years it is now a runner. All the work I have done, I have done myself. I have replaced the entire floor, taken it back to it's original colour, refurbed the carburettors and petrol pump, repaired the fuel sender unit, replaced the cam gear and all internal gaskets. I have sorted the timing, again with help through this forum. In short, we have bought this car back from the dead.

All the electrics and lights were working fine a few days ago, until I pulled the light switch a few days ago and it started smoking. I haven't used it since and have disconnected the battery.

All help I receive through this forum is very much appreciated. I am unsure of how to fit a head light relay, and how this will help, but am willing to tackle it if it will resolve the issue. Any further advice would be greatly appreciated.

Many thanks for your help

Andrew
Old 06-28-2020, 09:13 AM
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Andrew
Glad to help if I can. A headlight relay takes the actual electrical load off of the hl switch. Once set up the headligt switch turns the relay of and on, and the relay does the actual electrical connecting of the lights to 12v power supply. Here’s an example sold by our host, but you can source something similar locally.
https://www.pelicanparts.com/More_Info/JWSTERLYHLPR.htm?pn=JWST-ERLY-HLPR&bt=Y&fs=0&SVSVSI=5856
Good luck,
Bill
Old 06-28-2020, 11:16 AM
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Thank you! That's great. I will give it a go.

Many thanks

Andrew
Old 06-28-2020, 11:32 AM
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Headlight relays will not solve your underlying problem; you must find what is causing smoking in the vicinity of the headlight switch. Your very first job should be installation of a battery isolation switch so that you can terminate power to the entire car in case things start to go rapidly sideways during your diagnostic efforts.
Old 06-29-2020, 08:48 AM
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Thank you for your advice. I will look into doing that too.
What I don't understand is that everything had been working fine, and then this just started happening when I put the headlights on.

I will go through everything with a test light too.

Thank you for your help, I do appreciate your advice.

Best wishes

Andrew
Old 06-29-2020, 11:18 AM
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Andrew,
No fuses blown ?
Check if the cable for the instrument lights is not frayed and touching ground, this cable is not fused.
Are all the cables at the headlight's connectors firmly attached? One can be loose and touch ground, most probably this is not the case if that happens a fuse would blow.
Old 06-29-2020, 08:29 PM
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I read again your post and you say, that it works fine while you pull one notch, then the instruments lights' cable is not the problem.
Old 06-29-2020, 08:43 PM
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Hi,
Thanks for your reply.
There are no fuses blown, and I haven't changed any wires, but I will check for any frayed wires. The only thing I can think of is something to do with the ignition switch, as it has started to not make contact when you turn it to the second click to start the engine.

Well, I have plenty to be getting on with!

Thanks for all the help

Andrew
Old 06-30-2020, 02:15 AM
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Please be certain that nowhere on your wiring harness does it say "Lucas".
Old 07-01-2020, 05:56 AM
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Forgive me...It was just too easy...
Old 07-01-2020, 05:59 AM
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Man I guess there’s no joking with some people and Bowen did you not read ejboyds long answer just above yours?
People who whine because they don’t like the “tone” of people trying to help them wouldn’t get my help.
Good luck on your problem but if you’d lighten up a bit you’d probably get more help and if you put you location you might even get someone to come by and help you in person.
Tony
Old 07-01-2020, 06:15 AM
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Peter if that is the problem there is an easy fix for it.


Andrew I know you have a serious problem, but I could not resist to make a joke.
Old 07-01-2020, 01:37 PM
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donporfi: Excellent!
Others: geez, I agree...lighten up!
It's s'posed to be a fun hobby!
Old 07-01-2020, 05:48 PM
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Thanks to all of you that have offered help. The problem is now sorted.

Many thanks

Andrew

Old 07-02-2020, 10:42 AM
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