Euro Fog light replacement, No power to fog plugs Options

[Bucci]

Good evening gentlemen, I haven’t drilled down on any of the forms to find out the troubleshooting procedures.

1. I tested fog lights independently with 12 V source (working)
2. I hear the relay when I operate the highbeams.
3. All fuses appear to be good, I spun all the fuses under the dash for corrosion and connection.

My thought is the fog light switch may be bad, but it feels like all wires are connected. There is a green light that comes on when the switch is active

If anybody’s dealt with this lately. I need to check a Porsche manual to see what fuse is connected to the fog light circuit. I’m sure it’s one of the red ones.? I have brand new fuses in the glove box. I may replace them “all” but I did that 10 years ago. lol

Thanks,
Marc

[Dave_Darling]

Look to see which relay has the following wires plugged into it:
Red/Black (red with black tracer stripe)
Gray/Red
White/Yellow
White/Blue

That's the fog light relay. The white/yellow is the wire that feeds both fog lights.

--DD

[Bucci]

Look to see which relay has the following wires plugged into it:
Red/Black (red with black tracer stripe)
Gray/Red
White/Yellow
White/Blue

That's the fog light relay. The white/yellow is the wire that feeds both fog lights.

--DD

Dave, thank you for your expertise. I’m still in the hunt but getting closer..!



Tonight I was able to energize the fog lights manually by pressing down inside the round relay after pulling the round relay cover off.

What I’ve deducted is there’s possibly a grounding wire on the column stalk switch or headlight switch that signals the fog light relay to be energized. I think there’s an issue with the headlight switch or maybe the fog light switch wire has come off the main headlight switch..???

I probably should look at a wiring schematic to see what color wire goes from the fog light switch to the main headlight switch.

[Bucci]

Look to see which relay has the following wires plugged into it:
Red/Black (red with black tracer stripe)
Gray/Red
White/Yellow
White/Blue

That's the fog light relay. The white/yellow is the wire that feeds both fog lights.

--DD

Dave, thank you for your expertise. I’m still in the hunt but getting closer..!



Tonight I was able to energize the fog lights manually by pressing down inside the round relay after pulling the round relay cover off.

What I’ve deducted is there’s possibly a grounding wire on the column stalk switch or headlight switch that signals the fog light relay to be energized. I think there’s an issue with the headlight switch or maybe the fog light switch wire has come off the main headlight switch..???

I probably should look at a wiring schematic to see what color wire goes from the fog light switch to the main headlight switch.

12-29-23
Tonight I was able to remove the emergency lighting switch from behind the dash face and I removed the headlight switch from the back of the dash face. Both switches appear to be operating normal, and all wires are intact.

Also, I removed and inspected the turn signal and emergency flasher relay that is mounted on a sheet metal lip underneath the dash behind all the switches to the left of the steering column. I found an article online to diagnose and repair the relay, which I believe is working correctly.

This is for reference only. http://katdash.com/wp-content/uploads/2016...a2479-short.pdf.









My next course of action is to remove the steering wheel and horn ring then replace the steering column “stock-switch” that is used to activate turn signals and headlight “brights”.

I’ll have todo that sometime next week. Tomorrow morning I’m headed down to (San Diego) to Gillespie Field airport to help a Buddy change oil and check tires on a 1950 Cessna 170’ passenger airplane.