Homer43

My volt meter gauge randomly works. Usually it does not work with the needle sitting at the bottom. Any ideas? Thanks!

WICruiser

Could be either circuit foil on the back of the cluster or just that the nuts that hold the guage tight and provide the electrical contact are loose.

Either way you need to pull the cluster to check the foil, guage, and wiring connections to the cluster.

Homer43

ok thanks for the info!

Bart-Jan

I have the same and it's getting worse. I once noticed that at the moment it started working during a trip, I drove over a hump (stiff suspension), the needle swung up high, going down to a stable 12V. It usually reads quite low, but I've never had a low battery (knocking wood), so I figured the needle is a little 'sticky' and might need some WD40. Never tried it though. Anyone else had the same impression/solution?

Homer43

If mione decides to work it is always upon starting of the engine and will usually work until it is shut off. Then it decides to take a napp! I hate electrical gremlins! Thanks!

jtrygstad

This might help, too.

http://www.stuttgartperformanceengin...SHPROBLEM.html

Landseer

I'd probably trace the circuit from the alternator back towards the dash.
That way I'd ensure all the easier basic wiring stuff is right before getting into the more fragile instrument panel.
Gives a chance to inspect 14 pin connector and fuse/CE panel, and so head-off other issues.
Disconnect battery first.

Wiring diagrams are pretty good for 82.

Some places where there can be problems in the circuit, prior to getting into the dash pod:

Little black wire at alternator can be broken inside the insulation and touch intermittently, often in the 12 inches leading to alternator.

The little black wire runs through T14 (14 pin connector in engine compartment, right fender}. Corrosion or solder joints for wire at position 1 (the black wire again) can be bad and make intermittent contact or have an intermittent short with another circuit housed in the terminal block.

Terminals O8 and/or H8 at CE panel might not be seated. Make sure they are seated well and clean. In general, cleaning and re fusing the CE panel is a good idea if not done recently.

Path
black little wire at alternator
In/Out of 14 pin connector at terminal 1
Into CE panel at plug O, terminal 8
Out CE panel at plug Z, terminal 6 (to alarm)
Into CE panel at plug Z, terminal 1 (from alarm back to panel)
Out CE panel at plug H, terminal 8 ... now on its way to dashboard.

With a voltmeter set to measure resistance / continuity, and a 10 foot piece of extra wire, you can check for continuity from the alternator to each node mentioned just above. Worst part is dropping alternator and pulling its back cover off. Be sure to disconnect battery first though.

If you hate electrical gremlins, best approach on 928 is full frontal attack on all demons. I couldn't read an electrical diagram before ownership, btw.

WallyP

Landseer said, " I couldn't read an electrical diagram before ownership, btw."

And now, almost half of your cars have almost worthless diagrams. I hate having to go thru the '83 and '85 diagrams trying to solve a problem on an '84...

Randy V

Model year?

Read the New Visitor FAQ Topic at the top of this forum, please.

ReefShark

Watching this thread closely for solution... Mine does the same, some days it works perfect, other days, it jumps between 11 and 13 volts, other times it will just drop to nothing. However charging system is ok.

Landseer

The 84 car with which I began this odyssey had crispy wires throughout.
So I learned on 84 diagrams.
Mapped every CE plug in excel.
I think I have it for 84 Euro and USA.
Now all the other diagrams seem easy in comparison.

The OP's car appears to be 82 from past posts.

Homer43

Thanks for the advice. Yes My 928 is an 82. I will start checking all of the above week points first. Thanks again!