[53Rick]

I'm back after a year or so and working again on the '72 GMC fuel gauge/sending unit problem. I ran the ohms test on the sending unit and it did fine 0-90 ohms in the test. The sending unit wire runs to the fuse box where it connects to the wiring presumably down from the dash harness. A voltage check at the fuse box, though, shows 6 volts. Same at the end of the wire attaching to the sending unit. It is properly grounded and I even attached extra ground wires. When disconnecting the sending unit wire at the sending unit, the gauge goes from empty to full with the ignition switch on. Doesn't sound like a gauge problem, right? But what about the 6 volts at the fuse box? Several people told me it should read 12 volts there and they suggested running a jumper wire from a 12-volt location to the connector for the fuel gauge/sending unit. I did that and fried the sending unit and the fuel gauge went from the empty to 3/4 past full and stayed there. Back when this started, the problem was the gauge would never read full. It would go only to 1/2 tank when the tank was full. Then it dropped to empty and stayed there. I replaced the sending unit twice and also the float. Today I discovered the new brass float had a pin hole in it as did the new one I had previously installed, so that probably was the cause of the gauge not staying at 1/2-tank and dropping back to empty after a day after installation. I may have resolved that problem, but since the sending unit is/was (until fried) good on the ohms reading, what's up with the gauge not reading past 1/2 tank? I'm guessing a weak gauge, though I am still confused about the 6-volt reading. I've ordered a new sending unit, a new gauge, a new sending unit wire and a new printed circuit. Is there anything else anyone can think of that might be causing this problem? Thanks. Rick