I have a 79 C20 with the dual side saddle tanks. The driver side tank works fine and the gauge shows the correct level, But the passenger side shows way over full. Full on the gauge is at like 1:30 and the gauge swings to 3:00 when I switch to the passenger tank. I dropped the tank last night and the wires are all hooked up and the ground on the frame rail is making contact. Does anybody have a wiring diagram to show the wires for both sending units to the gauge? I have on wire running inside the passenger side frame rail that comes from the harness by the starter. That orange wire plugs into an orange wire at the switching unit area, which goes into a harness. In that harness, theres a green wire which plugs into the switcher and an orange-ish wire that plugs into the top of the passenger sending unit. And the harness runs along the bottom of the carriage cross member to the other tank, and then i believe back up the driver frame rail to the wiring harness to to gauge. I did not drop the drivers tank, but is it possible that the short in the wiring is above that tank some how? I put a test light on the plug in the top of the pass. sending unit and it showed a low voltage. I unplugged the orange wire coming from the starter wiring harness and it showed the same voltage. With that wire unplugged, the wire on the sending unit showed nothing. The green wire shows a strong 12 volts to the switcher. And the third wire shows a lower voltage. Please help. any diagram for the wiring would be appreciated. I'd hate to have to go buy an 80 dollar sending unit for the passenger tank if that is the problem.
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