Another Temp Gauge Question

[englands 71]

My temp hand is pegged on H.
I ran a ground wire from the bottom nut on the gauge to the windshield wiper nut (just to see if it moved) it smoked the printed circuit board. I can see where it burned the copper wire on the circuit board. I'm going to buy a new board tomorrow . Is there anything else I should buy and/or do while I have the dash cluster out . I don't want to buy one and trash it again . Why did it burn it when I touched it to the wiper nut ?

[VetteVet]

Originally Posted by englands 71

my temp hand is pegged on h.

your sending unit is bad or the wire from it is grounded, or the gauge terminal is grounded. Disconnect the sending unit on the engine and see if the gauge moves. If it doesn't the wire may be grounded. Check the diagram below.


i ran a ground wire from the bottom nut on the gauge to the windshield wiper nut (just to see if it moved) it smoked the printed circuit board. I can see where it burned the copper wire on the circuit board. I'm going to buy a new board tomorrow . Is there anything else i should buy and/or do while i have the dash cluster out . I don't want to buy one and trash it again . Why did it burn it when i touched it to the wiper nut ?

you shorted the copper strip to the grounded nut on the wiper motor. Which post on the gauge in the diagram did you connect to the wiper motor nut?


the two horizontal post on the gauge are supposed to be insulated from the cluster body. If the right side (12 volts hot) is shorted it will burn up the copper strip. If the sending wire post on the left side is shorted to the cluster body it will cause the gauge to read hot all the time (key on ).

[englands 71]

Originally Posted by VetteVet

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Attachment 1445431

I touched a wire the the bottom nut and touched it to the nut on the dash that screws onto the wiper knob with the key on.

[englands 71]

The silver post

[Davidf]

The copper traces on the "circuit boards" can be easily repaired with a bit of soldering skill. Carefully peel/scrape back plastic covering broken ends of copper traces. Tin both ends of the broken trace. Place a piece of copper wire over the tinned ends and touch with soldering iron...done.

[VetteVet]

Grounding a ground shouldn't have burnt the copper strip. Check the resistor and make sure there is resistance between the two posts.

What about the other tests?

[englands 71]

pulled out the instrument cluster and the printed circuit was damaged where the main harness hook in. Put in a new printed circuit and fix my temp gauge problem.

Thanks for you help ! Problem solved.