Former VWDieselParts.com Forum

Hey guys,
What would cause a fuel gauge and temp gauge failure simultaneously? I'm thinking fuse, but when I checked the Bentley, it didn't mention a shared fuse for fuel and temp. I'm going to go start pulling fuses right now. I'll let you know what I come up with.

stueve

On Rabbits it is the ----voltage regulater and or assoiated wiring --a bad ground will do it.---test regulator that is apple pie.

hagar.

Where is the voltage regulator?

I just checked for fuses, and nothing seemed out of the ordinary. I DID take out the instrument cluster last night to fix the trip/od cog. Just to clarify, there is only 1 wire harness that plugs into the back of the instrument cluster right? As in, in total, on a 1981, there are two things that need to be disconnected: the speedo line and the wireharness. The system WAS working when I put it all back together. So I don't think I messed with anything while it was apart.
I don't know.

How do you test the regulator? I'm sure it's in the Bentley, but while we are here

So this morning my gauges worked!? Short or regulator or relay?

flaky connection probably. Those leaf connectors on the cluster plug can get oxidized and make intermittent connections, sometimes plugging them in and out a few times will clean up the contacts. Temperature changes can make a difference too, causing things to move around at the microscopic level, restoring a tempermental connection (or making it fail)

Same goes for a bad solder joint like on the regulator that lives on the cluster circuit card. In my career (electronics manufacturing), we have brought many old circuit cards back to life by desoldering and resoldering all the solder joints on a board. It's a bit time consuming but if you don't have access to a replacement it can be a life saver.

mine were both non-funcitonal when I bought the car......then a few weeks later they both came back on. problem solved

next time you have your instrument panel off.... clean the contacts for the main multi-connector on both sides being careful not to remove any of the thin metal printed circuit. You could use alcohol or any suitable contact cleaner.

I think the trouble is in the connections.

Be sure the nuts on the two instruments are secure at the same time.

If everything on the dash goes wonky it is usually the big connector to the cluster, but if it is just the temp and fuel gauges their common point of failure is the voltage regulator and/or (most often) the press-fit connectors to the voltage regulator.


Vince