Fog light wiring/ switch question.

[Johnr352]

Last night I turned on my headlights. Fine, then turned on the fog lights and my right headlight went out. Investigated and found the #4 fuse in Bank 2 in the front fuse box popped. A fresh one popped immediately. I noticed the #4 fuse had two wires, yellow and a gray. A little diagnostic and determined the gray wire is the culprit, as with it undone the headlights are fine, low and high beams. It seems the gray wire is related to the fog lights. I know this as, when undone, everything but the fog lights seems to work. Interestingly, when I turn on the light switch, and then turn on the fog light switch I get 12v between the gray wire and positive battery terminal. Bentley does not show a gray wire from the fog lights to #4, instead it shows a grey to #7. But, in the attached picture you’ll see the #7 fuse seems to have a gray going in and out of the fuse. Which does match Bentlry (ish). Bentley also shows Fuse #3 of Bank 2 as having the fog light switch wire which is not referenced in the Fog lights wiring diagram. Any idea on what’s going on here? Any ideas on how to diagnose which switch is bad? What else could it be? No continuity between the wire and ground, which makes sense, sort of, but I don’t understand why I see 12v between the wire and the positive battery terminal when the switch is on. Fog light switch, headlight switch or headlight dimmer switch

[E Sully]

I would recommend going to the light blue bar above and clicking on User CP, then either my Garage and Add Vehicle, or edit signature then adding year and model of your car so readers know what car you have.
In this thread I have the wiring on my friends '87. Check out post #7.
3.2 “conversion” wiring help
You posted '84 diagram, here is '86-on diagram.

[pmax]

The description completely lost me, would help if you can add the referenced numbers to the pic.

BTW that has seen some mods .... those look like the headlight relays in the foreground.

[Johnr352]

Sorry for the confusing post. I’ll do better. 1982 3.2 Targa. Yes. I installed the headlight relay. Dead simple and worked right from the start.

No problem with lights after the relay install. Months. Then, all of a sudden, I was popping the number #4 fuse (right low beam). I noticed that the #4 fuse had two wires - yellow and gray. When I disconnected the gray and replaced the fuse, the left low beam works fine. Everything does, except the fog lights don’t turn on. I’m perplexed, as Bentleys does not show a gray wire going to #4. So I’m trying to determine the routing for that wire and wondered if other ‘84s also have that gray wire or if mine is different. I was also wondering why I would see 12v on that wire only with the fog light switch on when I check w a multimeter against the positive battery terminal and this gray wire but do not see continuity when I check the gray wire to ground. I’m guessing one of my switches has failed but was hoping for some ideas on how to determine which was bad.

[Johnr352]

PMAX thanks. The first pic is just showing the referenced #4 fuse circled. I’d removed the gray wire that seems connected to the fog light switch. In the second pic on the right side I can see a reference to a gray wire connected from the Headlight Dimmmer / turn signal switch but that gray wire should go to Fuse #7. In the first pic, I do see a gray wire into the Fuse #7 spot. So I’m unsure why there’s a gray wire to #4 - when Bentleys indicates I should only see the gray wire to #7 (which I do).

[E Sully]

I believe you mistyped the year.

[pmax]

As a datapoint, #4 has a gray wire at the top ... for an 80.
https://forums.pelicanparts.com/porsche-911-technical-forum/471128-pics-your-sc-fuse-panel.html#post4629859

[Johnr352]

Originally Posted by E Sully

I believe you mistyped the year.

Sheesh. You are correct. 1984.

[Johnr352]

Originally Posted by pmax

As a datapoint, #4 has a gray wire at the top ... for an 80.
https://forums.pelicanparts.com/porsche-911-technical-forum/471128-pics-your-sc-fuse-panel.html#post4629859

Well yes, and to E Sully’s point, I mistyped. Mine is a 1984 and I have no wire at the top of #4. My perplexing gray wire was attached with the yellow wire at the bottom of #4.

Thank you both for your patience….