C2 Temp gauge function/operation

[Philip A.]

My '65 read 40 degrees hot with a resistor matched sending unit [confirmed with IR gun]. I just had the entire cluster restored and replaced the sending unit with one supplied by the restorer [calibrated for the gauge]. After installing all my gauge does not work at all! How mechanically/electronically does the gauge and sending unit function? How should I trouble shooot this?

[Ken A.]

Re: C2 Temp gauge function/operation

Call your restorer.

[John H.]

Re: C2 Temp gauge function/operation

My '65 read 40 degrees hot with a resistor matched sending unit [confirmed with IR gun]. I just had the entire cluster restored and replaced the sending unit with one supplied by the restorer [calibrated for the gauge]. After installing all my gauge does not work at all! How mechanically/electronically does the gauge and sending unit function? How should I trouble shooot this?

Philip -

The gauge gets 12V (pink wire from the fuse), which goes forward through the fuse block (green wire) to the sending unit, which contains a thermistor (temperature-sensitive variable resistor); current goes to ground through the thermistor, and that resistance determines the gauge reading.

With the key on, remove the connector from the sending unit - the gauge should peg to full cold (infinite resistance). Then ground the connector terminal to the engine, and the gauge should peg to full hot (no resistance). The gauge must be grounded to the cluster can to work (3 o'clock terminal as viewed from the back of the cluster), and the cluster must be grounded (spade terminal above the tach, black wire from the harness).

[Philip A.]

Re: C2 Temp gauge function/operation

John
Thanks. This is what I was looking for. All my other gauges work. Does this mean the cluster is grounded?
Phil

[Ronald L.]

Re: C2 Temp gauge function/operation

Philip, Some of my story is here is the archive just a couple of months back if you search on temp sender and fuel gauges.

I would expect you have a grounding issue on that temp sender where it attaches to the cluster but can't say for sure unitl you have followed the diagnostic John has supplied to see where you're problem is.