Always like strange electrical oddities. My 93 GTS.

So, if I pull and hold the turn signal stalk the fog lights light up, the headlights rise and flash as I pull the stalk.

Stop pulling the stalk and headlights stay up.

Car has an aftermarket radar detector and battery drain.

Also, the left led in the instrument panel is dimly lit with the car off. If I disconnect the battery and reattach the led stays dark.

I've been putting off yanking the radar detector but I think that will be my first step.

 

I failed to mention this is with key out of the ignition.

All my other cars simply flash the fog lights.

Kevin

 

mine cycled upo and down. You need to replace the big, double headlight relay - that's likely the culprit. That is what solved mine

 

Thanks. That's an expensive relay.

 

yes it is. Try cleaning grounds first, in the pod, and clean the stalk.

 

Think the stalk should be flashing the auxiliary high beams in the bumper next to the fog lights, not the fog lights, right?

 

Probably.

 

Swapped in another relay from an 89 and the headlights continue to come up and flash.

I recently fixed a non canceling turn signal but how would that raise the headlights?

 

I never got to the bottom of it. I first replaced the relay with a new one ($$$) from Roger, that did not work. I then pulled the pod and cleaned the grounds, that did not work either (I actually had pulled it first to do other work, and had already cleaned the grounds, but I re-did them to be sure). I then pulled the signal/wiper combo switch and cleaned it, and that did not work; I put the old relay back in, and finally, everything worked fine. No more cycling headlights when I flicked on the high beams or turn signals, and I got my fog lights back (I also swapped out the fog light switch from the pod with one I knew worked). I then put the new headlight relay back in and it stayed fixed. I'll never know for sure, but it was trial and error with all of those things.

 

The 87-90 cars use a different relay (928 618 107 63) from the 91-95 cars (928 618 107 64). That may explain the issue with your test relay from an 89.

It's also possible they mangled up the wiring during the radar detector installation and that pulling on the high beam stalk also triggers the full headlights connection as opposed to just the high beams in the bumper, so if it's not the headlight relay itself, it is probably wired wrong so the relay gets the wrong input signal.

 

They've all been superseded to 928 618 107 64. A part number change according to AutoAtlanta.

928GT:
Relay - Headlight 87-95
928.618.107.04 (SC to .64)
The K40 radar set up was powered and grounded via the wires to the white radio plug.

The CE panel is very tidy. Only one wire associated with the air fuel/injector pulse display.

I removed all of that.

In my head I cannot understand how power is getting to the headlight motor.

​​​​​​​I'm going have to start at the headlight motor and work my way back.

Kevin

 

AFAIK the 928 618 107 01 relay - for 87-90 MY - was superseded by 928 618 107 63. The 928 618 107 04 relay - for 91-95 MY - was superseded by 928 618 107 64. I am pretty sure I got a 107 63 for my 89 GT when I replaced mine a few years ago, and that is also what Roger's site says (see 928 618 107 63 - Headlight Relay - 1987 to 1990 | 928sRus, Inc. and 928 618 107 64 - Headlight Relay - 1991 to 1995 | 928sRus, Inc.). I don't know what difference between the two is, but it is POSSIBLE that the test relay from your 89 is the 107 01 (or 107 63) part which may also result in the observed behaviour with the test unit as well.

Working back from the headlight motor is always the surest way, but very likely the most time consuming as well... as in you'll spend 40 hours on it instead of just 38.5.

 

Looking at the diagram, both wires to the motor go to straight to the headlight relay. It can't be a short between the motor and the relay, otherwise your motor would operate randomly and not when you pull the stalk.

The one weirdness is N21. It looks like one of the motor wires has a junction into the relay, but then just terminates at N21. When you're tracing through the system, to solve my morbid curiosity, is there a wire in the loom that runs from that plug into the car?

 

Yes - never the fogs.

Alan

 

It was an issue in the combo switch - you have in close proximity battery power, 56, 56a, 56b. And that particular part is a very fiddly bit...

Alan