Friend has a 2001 2500. The lift pump(I think, sounds like the fuel filter but pump is right under it) turns on and off when ever it feels like it. turn off truck may or may not stop. truck off sitting for an hour desides to turn on(just the pump).
Clark

 

gremlins sounds correct... hows his ignition switch. worn?
if its too much to deal with . run a hot wire from the battery mwith a switch. thats what i had to do for a while..
doesnt sound like a pump problem, more of a switch/relay problem.

 

I think the switch is good(nothing else comes on when key is off and pump decides to run.They are telling him he needs a new computer. Is the pump controled by computer or just a switch controled relay and/or pressure switch.
Clark

 

Computer commands the relay on. Could be a bad relay or a wire shorted to ground.

 

My bad! Heres the wiring diagram. They could be right needing a module. However the module should have no power. Might be an ASD relay problem or again, some type of wiring problem.