There may be 1 of 3 things wrong here, 1) bad gauge, 2)grounded wire or 3) bad sender, but to pinpoint youll need a wiring diagram print out. I suggest to bring it to a shop for diag or if you are good with circuits, just ask them for a print out of the diagram and figure it out yourself! Read full answer. Dec 13, 2010 • 2004 Chevrolet Avalanche.