gearz

I've got this wierd electrical problem on my '88 that's driving me crazy. Here's the problem(s) which I believe are somehow related:

1) When the headlights are on they (and the auxiliary headlights) flash from low to high beam when the left turn signal is applied.
They flash at the same frequency as the turn signal. The turn signal also works at the same time. Right turn signal doesn't make the headlights flash and works fine. As long as I never turn left I'm OK but it makes it tougher to get home from work...

2) Pulling back on the turn indicator stalk causes the headlights to flash as designed but also makes the left front and rear turn indicators flash too. Same thing happens with another multi-function switch so I don't think the switch is the problem. Just sitting in the car with everything turned off pulling back on the indicator switch will activate the left front and rear turn signals.

3) With the headlights on activating the emergency flasher switch on the dash will make the headlights flash from low to high beam just like they do in problem #1.
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Well I know that sounds crazy but believe me it really is happening. So far I've done the following:

Cleaned all pertinent grounds. Replaced hazard relay. Replaced multi-function switch with another--no difference. Problem #3 occurs even with the multi-function switch removed from the system. The headlights seem to function just fine, don't think anything is wrong with the system or the relay.

Somehow these two circuits (left turn signal and headlight flasher) have come together so to speak. I've exhausted ideas on how to fix this other than take it to a good mechanic who knows 928's but I'd rather not give in. I've never met an electrical problem I couldn't beat yet but I am a little worried about this one. I have a volt/ohmeter and a lot of patience.

What I need is a specific troubleshooting plan for my problem. Can anyone help me with this? Much appreciated! She's perfect otherwise!

dprantl

Have you looked at and behind the fuse panel for signs of anyone messing with the wiring in the past?

Dan
'91 928GT S/C 475hp/460lb.ft

Ducman82

sounds like a bad multi-function switch to me.

gearz

Sure doesn't look like anyone has messed with the wiring in the past, but you never know.

gearz

I thought that was the problem too so I replaced it with a different one. Same result. Granted, the replacement switch was used but "guaranteed fully-functional" by 928 Intl. What are the chances the replacement switch would suffer the same fault? It's $200 for a new switch, should I buy a new one, install it and pray that is the problem? If not then I would have 3 switches. BTW no return on electrical items....

Mrmerlin

has any work been done to the front or rear bumper where they might have been removed??
What was the last thing you fixed?

Ducman82

check your hazard switch as well. could be a short in it causing feed back.

Alan

Take the combination switch out and test it stand alone.

Turn Signal Terminals L & R should connect only to terminal 49a (when activated/side) and never to any others... verify particularly there is no connections from any of these to the headlamp beam selector terminals 56, 56a and 56b.

Alan

gearz

Thanks a lot Alan. I sure hope the switch is the culprit.

So then I should test for continuity between the pin @ 49a and the other turn signal pins (R, L, PL, PR and P) which would show the turn signal part of the switch is functioning but also make sure at the same time there is no continuity to any of the beam selector pins 56, 56a and 56b. Is pin 56 the same as pin X? My diagram shows a pin X to the left of pin 56a and no pin 56. Shouldn't be hard to do, I've gotten pretty good at removing the switch.

Alan

BTW its considered bad form to repost the same exact question in a different thread...

If you need to get attention simply repost to your own thread to refresh it to the top of the thread list... (you can just say "BUMP" or ask for specific additional help).

Reasons are its less confusing for everyone, data from you on the issue doesn't get split between two threads and others answers don't get split between 2 seperate threads... so its really better for you and everyone else if it all stays consolidated...

good luck - if it is the switch - it is possible to fix it - but its not for the weak willed... if so and you are willing I can point you to a thread on it... (nothing much to lose but time/temper...)

Alan

SharkSkin

Flip side of this -- make sure the corresponding wires in the harness are not shorted together. Disconnect the battery before sticking your ohmmeter probes in there.

76FJ55

Did you mention previously that the problem persisted even with the multifunction (column) swith disconnected if you turned on the hazard flashers? If this is the case it seem to me that it rules out the multifunction switch and leaves you needing to trouble shoot the harness in the car or the havard switch.

gearz

Finally fixed the problem!
First I tested the multi-function switch out of the car; worked fine, required 2 ohm meters to test it but could not find any fault. Pulled and tested the hazard switch, same result. Later I got to thinking the most logical place the two circuits could come together was at the CEP, especially after noticing the driving light terminal and the left front turn signal terminal were adjacent to each other. I then detached the panel and tilted it down to look behind at the connections. Everything looked good, no obvious problem with the connections. I was just about to put it back in place when I noticed a machine screw had somehow fallen into the area from above and was lodged in between the two terminals, effectively connecting them together. I knew at that point I had fixed the problem but it wasn't until I got the panel back up and the power reconnected that I could check and see if everything was back to normal. Cue drum roll: SUCCESS. All is well in my electrical world again.

Thanks to all who offered advice.

ROG100

I like happy endings

Stromius

Bravo bravo! Must be Otto's law (928 version of Murphy's) that has little screws hiding in odd places.