Gauge Issues

[KulpFarm]

Oil and temp gauge doesn’t work but t when I ground them out, the peg to the right. I added additional ground to motor and cleaned all existing grounds. Voltage regulatory in back of cluster is operation

What am I missing? Also, my dash lights dont work

[tsherry]

I just fixed dash lights on a friends truck.
His was a '71 F100. The back of the gauge cluster has a printed circuit--copper sandwiched between two layers of plastic. The exposed copper on all connections was green with corrosion. The lamps were twist-lock, with brass connectors that are supposed to contact the printed circuit.

I carefully cleaned all of the copper that was exposed until it was shiny again, same with the brass contacts on the lamp holders.

Still no luck.

Finally pulled the (good) fuse, but discovered that the fuse holder also had 'grey' corrosion, which is difficult to see. Cleaned that with an engine cleaning brush (brass) after disconnecting the battery.

That was successful.

One thing though, is that the rheostat on your light switch could also be toast, which might be the cause of your dead dash lights.

RE: gauges, if the printed circuit connections are corroded, no juice will get to the gauges from the harness. Use a multimeter to verify that voltage is getting to those connectors on the harness, ahead of the gauge cluster.

[KulpFarm]

Took a quick look at fuse block. I have a good fuse and did a quick cleaning of terminals (will need to take a closer look when I get time). New circuit board and headlight switch installed. Fuel gauge, turn signal and high beam indicators work. Also clean bulb socket contacts for good measure

[KulpFarm]

Got the oil gauge working. The sender unit for for the idiot light and not the gauges. I don’t know what is worst, the idiot that put it in or the idiot that missed it (me). Could the same be said for the temperature sensor?

[sparky72]

It’s certainly possible. I would replace it anyways, because a sensor system that you can’t trust is worse than useless, whether it’s for oil, coolant, or otherwise.