hey guys. 1990 f150 4x4 e4od 5.8. truck was running great. went to store shut off came back out and it only cranked. no front pump noise at all. switched to rear tank and she fired right up. so help me out here. cant be relay switch cuz theres only one and rear pump works. cant be inertia switch cuz back pump works. not a fuse cuz back pump works. so does this narrow it down to the switch and or the pump itself? so if i apply 12v to the red wire going to pump and it works then its the switch. if it doesnt then its the pump. is that correct? if not whats the best way to check things out? it does have about 150000 miles on her but well taken care of. pumps are original. i have a body lift on so would it be easyier to pull bed off to replace pump instead of dropping tank? thanks guys.

 

Yes it would be the switch or the pump. More than likely the pump.
Sounds like you have a good trouble shooting method.
Yes it is very easy to change the pump once the bed is off.

 

it was the fuel pump. i dropped thetank not to hard since i have a body lift and 35 in tires. only one bolt gave me a hard time. also found gas leak under the holding strap/band. will put back together tomorro.