The gauges in this 83 HO all seem to work except the fuel. I got a new sending unit and it bench tested fine but gauge reads E with a few gallons in it. If I put a test light on the one hot wire going to the sending unit, it should light right? If it doesnt I assume there is a break in the line? I hate working with electrical....

 

With the key on and the ground wire coming to the sending unit disconnected from the sending unit, the gauge in the dash should go well past full. With that same ground connected to ground it should go to empty.

Yes I think the one wire should have battery voltage to it with the key on.

 

The wire going to the sending unit from the gauge is actually the ground side of the circuit.

 

Well, I went to the museum to get the service troubleshooting walk thru and tested everything. All came back right. Looked up capacities and found its a 20 gallon tank. I thought there was roughly 5 gallons already but wasnt sure. Put in an additional 3 and the gauge is at 1/4 tank now which should be pretty spot on. Im a f#cking idiot....

 

Thanks oldcutlass, makes sense.