Instrument Cluster

[hewilson2]

I recently purchased and installed a restored instrument cluster - said to be compatible with '83 through '86 - for my '85 G30. The temp gauge was working on the original but is not working on the restored cluster.

The seller insists it bench tested just fine and instructed me to be sure to connect the wire from the temp sensor.

Well, when I removed the original, there was no wire specifically to the temp gauge. There was only the wiring harness and another 12v wire to a light bulb that presumably powers all of the light bulbs. But nothing directly to the temp gauge.

My question is, assuming the seller is correct and the temp gauge is functioning electronically, what could be the issue? Could there be a compatibility issue with my year of 1985 and the cluster is from a different yer?

Any help you could offer would be greatly appreciated.

[MountainManJoe]

The sensor could be bad. Verify by getting an ohm reading on it.
Or the wiring is bad. Test continuity between sensor and cluster harness.

[hewilson2]

Thank you for the reply. I will do that but...the gauge was working before the instrument cluster swap and no apparent visible damage happened to the wiring harness in the process. But I suppose something slight could have occurred that I missed.

[MountainManJoe]

Well you have to eliminate the possibilities one by one. I thought the instrument panel tested OK, but it sounds like you are suspicious of it. Well, the guage can be tested too. Find a wiring diagram for the cluster, and hook up a temperature sensor directly to the cluster and drop the sensor into some hot water.