Originally Posted by racine
My 1990 F150 4X4 won't run when the rear fuel tank is selected - tank is full, gauge properly reads full, engine dies immediately, quickly restarts when front tank is selected.
Does anyone know of any web source where I can download a wiring diagram of this portion (dual tanks, in-tank fuel pumps, selector switch, relays) of the electrical wiring system for this truck?
Sounds like you need to pull the bed and replace the rear FDM (Fuel Delivery Module).
Here is the diagram you wanted:
http://i54.photobucket.com/albums/g91/subford/Fuel/Fuel-sel1990F150.jpg