Latest update. Went into town with the truck and the gauge was still showing full but while coming back the gauge would move erratically from full to empty. That was new had never seen that. When I got home the new resistor was in the mail and I proceeded to install it. Once installed and key turned on it went to full. Same thing as without a resistor with direct 12v. Reading the installation/diagnostic sheet that came with it, the last item said “if the gauge only shows full and you know less fuel is in the tank the problem is the wiring to the sender or the sender itself. Run a jumper from the sending unit to a good ground, if the gauge goes to empty, the sending unit is bad” Well the gauge went to empty, so I guess it’s time for a new sending unit?
