Temp & fuel gauges - what am I overlooking?

67Dart273 said
Well if the cluster/ gauges pass the test resistor, then it HAS to be either in the body wiring or the sending units, if you tested it "in the car." You can eliminate the body wiring by putting the resistor right at the sender connector to ground. Should get the same result.

If you tested the cluster out of the car, you have the additional possibility of a cluster grounding problem and a possible poor connection feeding 12V from the key to the cluster

But the body wiring must be good because grounding the sender wire causes the gauge to go toward full. Ditto grounding and 12v to the cluster. If there was a problem in the wiring, ground, or 12v feed the gauge wouldn't work at all.

It's all confusing. That's why I tried everything I knew to try including replacing a good IVR to try to get them working before posting for help.

harrisonm said
I have tested these gauges before with two AA batteries. The IVR puts out a pulsing current of about 5 volts. I tested them by placing two AA batteries end to end for 3 volts and then running two wires (one from the + end and one from the - end of the batteries) to the back of the instrument. 3 volts should move a gauge that needs 5 volts to go all the way up to about 2/3s of the way. I assume that this test method was safe. I have done it many times with no problem.

I'm going to give this a try.