Temp guage malfunction
 

What is the symptom when the resister on the back of the temp and fuel guage needs replacement? BOTH MY GUAGES PEG OUT WHEN IGNITION IS TURNED TO ON AND BEFORE STARTING.:gmc:
sORRY GUYS...THIS IS A 1972 jIMMY

I would start by checking the gas gauge sender/wiring. Ground the brown wire at the fuse panel, if the gauge goes to "0" then the problem is in your wiring or in the the sending unit.

On the temperature gauge, I would check the green wire going to the block sensor. If the gauge goes to cold with the wire disconnected, then the sensor is bad or you have the wrong sensor. If the gauge reading remains on hot, I would check for grounding of the green sensor wire.

Dash units are usually good and the problems are usually elsewhere.

Good luck!

Jim