I have a question about the gas gauge in my 52 Chevy truck.I put a new wiring harness in the truck and a new ammeter gauge with a new 12v gas gauge.The gas gauge is wired according to the instructions with the new wiring harness but it doesn't work.I reversed the wires on it and nothing.I put it back to the original way and grounded the sending unit wire and the gauge still didn't react.What could be the problem.Thanks for any input on my problem.