How do I test my headlight switch?

[grogthegreat]

Hi,
So I had my original headlight switch go up in smoke in my 68 912. I got a used replacement switch from these forums but after the install my headlights and running rights still don't work right. Since this car is new to me, I don't know if my problem is in the switch or if I have a different electrical issue elsewhere.

What I need to do it test the headlight switch with an ohm meter to find out if it is working correctly. As you know the switch, 911.613.029.01, has a large number of spade connectors on the back and the electrical diagram I have isn't clear on what connectors get connected and which ones don't in each of the three switch positions.

Can someone please share this info? I've searched on here and was surprised when I couldn't find this info.

Thanks!
-Grog

[86 911 Targa]

Originally Posted by grogthegreat

Hi,
So I had my original headlight switch go up in smoke in my 68 912. I got a used replacement switch from these forums but after the install my headlights and running rights still don't work right. Since this car is new to me, I don't know if my problem is in the switch or if I have a different electrical issue elsewhere.

What I need to do it test the headlight switch with an ohm meter to find out if it is working correctly. As you know the switch, 911.613.029.01, has a large number of spade connectors on the back and the electrical diagram I have isn't clear on what connectors get connected and which ones don't in each of the three switch positions.

Can someone please share this info? I've searched on here and was surprised when I couldn't find this info.

Thanks!
-Grog

Your switch P/N has been superceeded to 911-613-029-03.

For our '86.

Hope this helps:



Also:

http://www.cannell.co.uk/Manuals.htm

Good luck,

Gerry

[grogthegreat]

Thanks for the reply. My switch is still the -01 version. It has the same connectors as your pictured switch so I'm not sure what changed.
Unfortunately that picture doesn't help me test the switch. The wiring diagram I have tell me what wires to hook up and it is pretty simple to follow those traces on the diagram to find out what each one goes to. I'm not worried about installing it incorrectly but rather I want to make sure the switch I'm installing is working properly. What I need is to find out which connectors connect to which spade connectors for each of the the three switch positions. Armed with that info I should be able to grab my ohm meter and test the switch.

[86 911 Targa]

Originally Posted by grogthegreat

Thanks for the reply. My switch is still the -01 version. It has the same connectors as your pictured switch so I'm not sure what changed.
Unfortunately that picture doesn't help me test the switch. The wiring diagram I have tell me what wires to hook up and it is pretty simple to follow those traces on the diagram to find out what each one goes to. I'm not worried about installing it incorrectly but rather I want to make sure the switch I'm installing is working properly. What I need is to find out which connectors connect to which spade connectors for each of the the three switch positions. Armed with that info I should be able to grab my ohm meter and test the switch.

This is from my 1986 factory manual.

As for the -01 v/s -02 I don't believe there is any difference.

Also, have a look at the link I sent you.

Gerry

[grogthegreat]

Well since the information doesn't appear to exist on these forums, I though I'd share the info I found for people searching in the future.

Here is what you should find when using an ohm meter to test your headlight switch:

In switch position 1 (aka; pushed all the way in):
57 and 58a will have a resistance between the two controlled by rotating the headlight knob. No other spades will have continuity with any other spade.

In switch position 2 (aka; one click out):
The spades 30, K, 58L, 58R, and 57 will all have continuity between each other. Spades 30, K, 58L, 58R, and 57 will have all resistance between them and 58a controlled by rotating the headlight knob. No other spades not mentioned should have continuity with any spade.

In switch position 3 (aka; all the way out):
Spades 30, K, 85L, and 85R will all have continuity between each other. Note that spade 57 is no longer part of that group. Spades 56 and 75 now have continuity between each other. Note that on very old switches (like the smoked one on my 68 912) there is no spade 75. On these switches, I suspect that spade 56 gets connected to the rest of the group when the switch is pulled all the way out. Also, spades 30, K, 58L, and 58R have the same variable resistance to spade 58a via turning the headlight switch knob.


I hope someone finds that info useful. It is possible there is a mistake somewhere in there so if you find one, please post it or PM me so that I can edit my post.

[Canada Kev]

There's a bunch of information on the switch and how it operates here. I had a buggered switch and had to figure out how it worked. If you have any specific questions that aren't answered in that thread, don't hesitate to ask. Good luck.

Headlights not working properly?