[recnepswilliams]

1980 camaro gas gauge. The printed circuit on the back of my dashboard is ruined, but i need the gas gauge to work, there are 3 terminals in the back of it, one on top, and two on the sides with what looks like a resistor between the terminals. Does anyone know how to hard wire it without the printed circuit on the back of the dashboard, all of the lights and everything were easy, i'm just stuck on the gas gauge.

It's the large fuel gauge to the right of the speedometer where the tach usually is.

[75gmck25]

Based on a diagram I have from an older cluster, the terminals should be sending unit wire, ignition-on 12 volts, and ground. I'm not sure the ground terminal is used.

I would try connecting 12 volts and ground to the two terminals that are connected by a resistor, and figure out which combination makes it swing to empty. The resistor is usually for calibration of the needle, so those should be the right two terminals.

On a GM gauge if you have 12 volts on the positive terminal and the other is grounded, that is an empty tank condition. If you put resistors between the sending unit terminal on the gauge and the ground connection, the gauge should show progressively higher, until you get to 90 ohms and full.

Bruce

[recnepswilliams]

So when i hook it up, i will only need to have 2 wires going to it? one ground and the other one would be the wire that originally went to it from the harness?

because i know when i took it apart there were 3 copper wires going into it from the original printed circuit.

[75gmck25]

The two terminals with the resistor should be 12 volts power, and sending unit wiring. The third terminal is grounded to battery ground.

Bruce

[recnepswilliams]

Thank you for the help, I traced the printed circuit back and found the sending unit wire in the plug behind the dashboard. I tested it and between it and the ground my tester showed some resistance, so i assume that's how the fuel gauge works.
I think i have it all wired up correctly now