Classic/Antique Car Repair: Fuel gauge 1970 Chevy c10 truck, 1970 chevy c10, jumper wire

Question
I just purchased a fully restored 1970 c-10 and the fuel gauge doesn't work.  How/where should I start to track the problem down.  All the fuses look to be ok.  Thanks, John

Answer
On a fuel gage problem I usually head for the fuel tank. Find the harness connector that will disconnect the fuel sender and break it. Run a jumper wire from the end that comes from the front of the truck to ground. If the gage reacts when grounded then the problem is in the tank or a tank ground. If the gage does not react then the problem is forward, in the dash gage, wiring, or ground behind the dash. This truck also uses a printed circuit board behind the dash and I have found those bad. But is is visual checking and checking with a volt-ohmmeter now. Good Luck.
Brad