I read your car talk guidance every weekend,and look forward to it. I have a problem with the fuel gage on my 2008 Chev. Super C diesel motor home 5500 which after 55,000 miles started reading either full or empty. I pulled the entire gage panel and had it tested by two different companies. Both said it was fine. I have pulled the 100 gallon tank twice, cleaned it, replaced the fuel pump and reader, but there has been no change. There was nothing broken on the wires, and when I plugged the wires together on the pump the reader on the gage operated when I moved it. The pump only goes in one way, in the center of the tank with nothing around it, but it doesn’t work. I have followed all the advice given to me by mechanics, and don’t know where else to go so thought you might be able to help me. I hope so.
If this was an actual 3500 Chevy I’d say the only thing left is the wiring itself. But this is a motor coach and Inhave no idea what the coach builder buggered up in the modification and assembly process. I’d still assume the wiring has a short somewhere between the gauge panel and the tank.
I would think that it is now time to let them fix it . They are probably making suggestions that they think a non-professional mechanic could do.