Gauge issues (minor)

I have notices that even with the fuel tank full, my fuel gauge does not read quite full. Is there a voltage regulator or stabilizer or something in the circuit that might cause that? (Probably could ground the sending wire and see if it reads full, huh. Might be the in-tank sender?

Secondly, today I noticed that each time my windshield wipers came on in the delay mode, the fuel gauge and temperature gauge needles would flick down slightly and then comes back up. Just perceptible.

Any idea of what might be going on here?

The coupling between wipers could be through the ground (ground bounce) or the 12V. Without having looked at the circuit to see what wires are shared, I would say ground bounce.

Arde said:

The coupling between wipers could be through the ground (ground bounce) or the 12V. Without having looked at the circuit to see what wires are shared, I would say ground bounce.

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Exactly. My temp gauge goes up when I turn on the headlights. Why are you using the wipers? :confused:

Seriously, the dash/instrument grounding is almost certainly the issue. You might clean / crush (or put in new spades) for the tank sender unit connections and clean the ground wire connection in the trunk area. I haven't tackled my instrument grounding issues but if I recall correctly the ground runs through a steel plate with a single tie point. To fix it I would probably add direct copper grounds to the different elements in the cluster. This is just plain old stupid 70's german electrical design; following in the footsteps of Lucas.

To John regarding the instrument grounding

I have had the instrument cluster out on several cars.
I have noticed the small arm at the bottom, which can be moved up or down being attached (riveted?) at one end.

Might the idea behind this be to improve the grounding, by pulling it down behind the body framework housing the instrument cluster.....?
I have never tried it, and when removing the cluster it was never in this lower "grounding" position, but this could be due to PO´s having removed the cluster and not reinstalling it that way (if it ever left the factory that way?).

What other function might it have?
The cluster is fastened by 2 nuts at the end of the long studs.

grounding

Gage bounce is famous/notorious if you have had a 2002. In that car it's usually a result of a poor instrument cluster ground. You can buff up the ground connections or install a separate ground to the body. Probably wouldn't be a good idea to check all the major grounds (body/engine, alterantor/engine, engine/battery).

pmansson said:

I have had the instrument cluster out on several cars.
I have noticed the small arm at the bottom, which can be moved up or down being attached (riveted?) at one end.

...

What other function might it have?
The cluster is fastened by 2 nuts at the end of the long studs.

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Never got to see that arm, but I am good at guessing what other people think. If you post a picture I can tell you the function they had in mind.