Bought the truck last month. Runs fine off the front tank. Previous owner said he always filled both tanks. But now I cannot switch to the rear. The tank is full. Flipping the switch does not change the gauge either.

Wiring to the fuel tank selector switch seems funny. The fuse marked Auxiliary Fuel has only a hot connection. The second slot is empty and no wire in back of the fusebox either. No power at switch terminals. The wiring harness to the switch looks original.

Is this wiring typical? Is there an inline fuse somewhere? Does anyone know where the trouble might be?

 

sounds like you're missing a ground or something. have you looked at the selector on the frame?? anything amiss there?

 

Doesn't sound at all typical, sounds like it's been Frankensteined. Look up your
wiring diagram on the below link, maybe it'll help ya.

http://www.autozone.com/az/cds/en_us...rInfoPages.htm

 

I used catsup to clean the connector at the valve on mine. I forced it into the plug/socket, let it sit for 20 minutes, then flushed it out with contact cleaner. After that, grounding the yellow wire made the gauge move. now I just need to replace the sending unit in the rear tank. I mangled the fittings when I took it out.