Headlight Switch Revisited

[JJG911]

I hate to revisit a subject that has been covered many times on this forem, but need some advice. Today I replaced the headlight switch on my 79 911SC with a used switch. I trashed the old switch while trying to remove it a couple of weeks ago due to the threaded nut being stuck. At that time I was replacing the turn signal switch due to broken headlight contacts.

The problem that I have now is that the headlights come on with the switch in the park light position and in the headlight position. All lights work correctly whether in the low beam, hi beam, or headlight flasher position and the turn signals work correctly. Any ideas why the headlights are coming on with the switch in the park light position?

[pete3799]

Mine works the same way (on at first pull) been that way since i bought it.
Someone here posted a good thread about it (and corrected it). I'll see if i can find it.

[pete3799]

Here ya go
Headlights not working properly?

[JJG911]

Thanks Pete. That appears to be the exact problem that I have. We'll do some rewiring tomorrow. BTW, being relatively new to this forem, what does "RoW" stand for in the Porsche world?

Thanks,

[pete3799]

Rest of World
Not made for sale in the US.

[JJG911]

Thanks Pete. My CoA says mine is USA model, so I guess its referred to as "non RoW". Finding information on this forem dealing with a similar problem sure saves me hours of testing and reading wiring diagrams. Now I can move on and install headlight relays.

[Canada Kev]

Pete has recommended a post that should help you sort out your little problem. If you can't figure out which wires are for what function, just pull ONE wire off at a time and see what stopped working. If it's your rear license light, you know that wire should be on pin N. It will also make a difference what position your ignition switch is in, as well. Some functions (like head lights) will only work with it in a certain position. You will note that in the H/L switch matrix in that thread.

When I was having a problem similar to yours, it was just that a PO had wired the head lights to work with the parks because the H/L portion of the switch stopped functioning. Your issue is a bit different, but the symptom and troubleshooting is the same. Lots of wires on the back of that thing so it's easy to mix 'em up.

That switch is a pretty simple way to change up lighting attributes, as well. For instance, if one wanted to be able to run the fogs without using H/Ls, just move the (probably grey) fog light relay trigger wire to a terminal pin on the switch when you wanted the lights to be able to turn on. Such as pin 75 (hot on run) to be able to use them only when the ignition is in the on position. Or on pin 30 so they would work any time. I used 75 so when I forgot to turn them off, they would not stay lit up when I turned the car off.

Good luck.

[JJG911]

Thanks Kevin. I switched the black/white wire to #57 today and now they work correctly. Park lights on when switch is in the middle position and headlights on when switch is in full out position and ignition is on.

Another problem has come up with the wiring change. The turn signals now blink fast in both the right and left positions as if a bulb is burned out, but all bulbs are functioning correctly. Any ideas?

Thanks!

[Canada Kev]

Your flasher/relay thing? Your switch shouldn't affect the flash rate. You could check the voltage at the back of your switch to ensure each terminal pin is correct for its purpose to make sure nothing is amiss. I wouldn't expect that switching the left and right parking light wires would matter, but double check that you got them right. I am assuming that they worked just fine before your switch swap. If so, it's probably one or more of the wires is in the incorrect spot. I'd suggest rechecking all of them.

[JJG911]

Thanks Kevin. I'll check the connections tomorrow and take some voltage readings. The one wire that was on #57 is grey and I switched it to terminal "K". Not sure what it feeds, but will get back tomorrow with some results.

[Canada Kev]

The grey one, especially if it is kinda fat, is probably your fog light relay trigger. If that's the case, your fogs will work when terminal K is hot. I don't know when that is, as I have no K on mine. Perhaps it is in place of N?