Intermittent Headlights

[MBellRacing]

Hey everyone,

So just looking for an opinion on what I should hunt down first...

When I picked up my 1986 911 a month ago, the right side parking light and right side city light were out. Both headlights worked, both high beams worked, both fog lights worked.

About 2 weeks ago, I noticed right side fog light was out and ordered a new H3 to replace it and some new BT9 bulbs to replace the side markers. At the same time, I decided to do the relayed headlight kit. Spent an hour or so installing everything. Fog lights turned on, side markers still were out, city light still out.

Move to a few days later, and the high beams would get stuck on and you could hear the relay click on, but turn off only after about 30 seconds-- EVEN WITH THE KEY PULLED OUT. I assume this is because the relay gets wired to the battery directly, but it was odd. I assumed, and still assume, it was just a sticky relay, as it went away on its own.

Move to another couple days down the road, and suddenly the left side headlight wouldn't turn on, but high beams still worked. Last night, I pulled the fuse cover and noticed the side marker light wire was barely held in by the fuse holder screw. I tightened it down and checked all the other wires. Suddenly, all the lights turned on beautifully, but upon rechecking, the fog lights were out. I turned everything off, then back on, fog lights worked. I went to bed happy.

So this morning, after thinking I had solved everything, I turned on my headlights, and my left main beam was out again and the fog lights don't work. I jiggled the living ***** out of the light switch and fog light switch, but since I was on my way to a meeting, I couldn't waste anymore time pulling the fuse box cover.

As stated, what should I look for/replace first? Is it likely the light switch? Should I double-triple-quadruple check the grounds and fuse holders [again]? Most important question: How likely was it that an English gentleman was working the Porsche wiring department in August of 1985?

Any help/guidance/talking me off the ledge will be appreciated!

[911 Rod]

I think you have more than one problem. The high beam/signal stalk might be shorting out and giving you high beam irregularities. Replace it. They can be a fire hazard.
The running lights and fog light contacts get corroded. I had to clean mine 3 times before they stayed on.
If you wiggle something and the light flickers, you have found the problem.

[MBellRacing]

Thanks for the advice! I forgot to mention, I did replace the blinker/dimmer stalk. No problems there, I don't think.

My dad, an electrical engineer, actually mentioned the same thing. He told me to remove all the fuses and steel wool them to make sure they have a nice connection. He figured the wires are in the right spot and the bulbs work. Something is intermittently connected, probably from corrosion.

[wrxnofx]

When I got my car the parking lights did not work, either. I removed the amber lenses and looked at the contacts. They were ridiculously green from corrosion on the copper. I used a dremel and wire wheel and cleaned everything up, along with a touch of dielectric grease. They have worked like a champ ever since.

You may have to pull the headlights to see how the city lights are wired in the bucket. That was problem #2 for me. My car spent years in the hands of a 3 star general, and it went wherever he went. One of those locations was Norway. If memory serves, the default wiring harness doesn't allow for wiring of both the city lights and the parking lights. So you have to make a pigtail to connect both lights up, which is what I did. There is a thread on here about it. Someone took the wires from the parking lights and connected them to the city lights (seemingly to make the car legal in Norway?). Thus, my parking lights weren't even hooked up.

Considering both sets of yours work intermittently, however, I would suspect they're wired correctly. Can't hurt to take a peek in the bucket just the same, though. If the seal around the headlight was perished, water could have gotten in and maybe corroded some of the connections in the bucket.