[j_gallagher]

does any know how to test your guages that are powered by the instrument panel voltage regulator? The origional one in my car quit working causing the guages to read high (maxed out). I have installed 3 new regulators (2 from CalMustangs, 1 from Carlisle car show) and all have caused different malfunctions. I know the fuel, temp and oil pressure guages are powered by this regulator. They operate on 6 volts so the regulator reduces the voltage. Anyone have a way to see if the guages are good and that i have gotten bad parts?

[The Greek]

I don't know if you are having a gauge problem or you don't have a good ground either for the senders or the gauge cluster. If you applied Teflon tape to the threads of the oil pressure and engine temp senders or a pipe dope that is insulative then the senders aren't going to have a good ground. Check for a ground with an Ohm meter set on the continuity mode or just the resistance mode. Place one of the probes on a known good ground and the body of the sender. If the meter indicates continuity you can eliminate those and go back to the fuel tank and check the ground to the fuel sender, a known good ground to the flange of the sender assy on the fuel tank.

Check the ground on the instrument panel. Sometimes I have found them connected and still not giving a good ground. All of the senders and gauges operate at 73 Ohms empty and 10 Ohms full or 73 no oil pressure or cold engine and 10 OHMs max oil press or hot engine. In actuallity all of these gauges are the same, they are just labled differently.

The gauge voltage regulator should put out a pulsing 5 Volts. 12 Volts in, pulsing 5 Volts out. If you ground out the sender wire for each gauge the gauges will show maximum.

I've had these regulators go out from time to time, but nothing like you're experiencing. Have you checked the connectors from the harness to the instrument cluster for corrosion? This is a potential trouble spot. One more thing to mention is that the polarity on the voltage regulator should be + for input (12 Volts) - for output (pulsing 5 Volts) The reason why it pulses is because of the way the regulator is constructed. The gauge needles don't have time to react to the pulses. Make sure that the harnesses aren't creating a high resistance, they'll do that after 40 years.

Good luck, ---Chuck

[j_gallagher]

chuck, this one can't be connected backwards. it has 2 wires connected to it. one wire has a male spade connector and the other wire has a female spade connector, so they can only be connected to the regulator one way. so i know that part is correct.

[j_gallagher]

think i got it to work. i took the instrument panel voltage regulator apart and found it to be a simple design. it has what looks like a thermal contact relay switch inside with a resister wire wrapped around it that is grounded to the case. mine had the very fine (hair thick) resister wire broken. i found you can't solder it, it doesnt stick. so i twisted the two loose ends back together. after reassembling it i installed it in the car with an additional ground wire from the mounting screw to a good ground on the lower dash (just for good measures). now all the guages are working but reading a little high. i think this is because when the wire was twisted together it changed the resistance because the wire length was changed.
hope this helps some else.
good luck to all who are having this problem.