Basically there are 3 connections on the back of the gauge, 1 is keyed +12 volts, 1 is ground, the other is signal wire from fuel sender. You can just run a seperate wire like you're talking and make sure you hook it to the correct termination on the back of the gauge. I don't know if GM changed the location over the years but I have a cluster in the garage that I believe came from a 75 truck I could look at and try to see if I can tell which termination is for the signal wire.
Ok, if you're holding the gauge in your hand looking at the backside of the gauge the terminal to the left is the signal wire from the sender, the terminal to the right is keyed +12 volts, and the last one is ground.
I dont know if this is the place for this but here goes. Bought a 75 c10, gas gauge didnt work, as a matter of fact none of the gauges worked, anyways got to checking and the fuel sending unit wasnt hooked up, hooked that up only to find out that it wasnt hooked to gauge/fuse box harness. im trying to find out what wire i need to hook this wire to. also i have 4 wires not connected at the gauge harness, a black wire, pink/black wire, pink wire, and a larger yellow wire. any of these it or can i bypass the harness all together and hardwire my gauge in? any help is appreciated and any wiring diagrams are welcome since how i cant find a SINGLE one that tells what wires are the dash harness wires
