electrical gremlins
 

I took my 1985 928S in to get its inspection done. When I picked it up I noticed that the clock was wrong. The next day I noticed that the interior lights didn't come on when I opened the door and that the clock had reset itself. As I was driving to work the clock started to flash and then went out and a warning beeper started going off. Something must have gotten knocked loose because when I would driver over a rough part of the road the clock would flash and the beeper would stop. Any ideas of what to check first?

How did you resolve the timing belt light?

that is still an issue I'm dealing with.

so I think I need to check the relay under radio in the center console. What is the best way to access it?

take out the ashtray to get to it

Well I eventually pulled the door chime relay so it would stop "dinging" and drove like that for a couple of weeks. This morning I noticed that the clock was working again along with the "PRND23" lights were working also so I put the door chime relay back in and now it works! But now the clock stays on until you open the door and the chime goes off and the clock and the "PRND23" lights go out too. And ideas on where I might find my gremlin?

What electrical maintenance have you done since bringing the car back into service?

The sequence typically is cleaning all known grounds (there are a dozen or so depending on year) and remove and clean all connections for the CE panel.

Its generally not possible to fix a thing here and there on these cars, at least not until the base is solid, so to speak.

Same thing mechanically. There are some achilles heal things that we've seen fail systematically with the age of the vehicles. Some can even kill the car. Some you.

Dialing in on this, some things that probably need attention (have on every 928 car I've touched):

Door pin switches, Hatch pin switch, CE panel grounds on firewall above panel, ground point under steering column area, ground point buried under passenger rear quarter panel.

The thing is, its more efficient to hit all the grounds and pull / clean the panel. Due the type of electrical fittings & materials of construction, the ground points start corroding and it causes a long slow burn of havoc that can be avoided with a more systematic refresh.

How's it driving / behaving otherwise?

Ive replace my turn signal relay since that quit working and checked all my fuses

Its driving great no other real problems

Cool.

Well, just some contact cleaning is likely all you need!

what is the best way to go about cleaning the contacts?

It depends. Physically, access varies and the type of connector or corrosion. On pins and spades, where moisture causes green corrosion, I use emery (sp) paper or xxx sand paper, lightly. On pod electrical or electronics (these are not copper) something less abrasive, others swear by a white eraser. Radio Shack sells a spray electrical cleaner that is supposed to be useful. In the New Visitor thread is a list or link of connections. In your case the first to do includes the 14 pin jump post, ground strap (it can look fine, but have internal defect)

dr bob instructions:
You can easily check ground strap integrity with a voltmeter. Leads at the ends of the strap, meter set on DC volts. Put a load on the system with headlights for instance. Reading on the meter is voltage lost through the strap. For most straps, anything bigger than a small fraction of one volt means the connections or the strap itself are suspect."

from this thread: https://rennlist.com/forums/928-foru...-switch-2.html