I'm working on an 86 c1500 that has been sitting for a few years. I finally got it running after a new battery and found a couple of wires that had been chewed up by field mice. Now wondering why the fuel gauge points at 3 o'clock all the time. I took the gauge out and getting power to the gauge, put the gauge to 9 o'clock and when I turn the key to the on position it goes right back to 3 o'clock. all fuses are good, duel tank switch does not change anything but but when pushed to the left tank position I can hear a clicking noise under the bed. would this problem stem from a bad sending unit?