Ford F150 electrical problem I think!!! HELP

My son has a 1996 Ford F150, his truck died on him the other day. We went and got a new battery - nothing. We had the alternator tested - it passed. We put a new cylanoid (sp) nothing, we changed the battery cables nothing. Now mind you everytime we did all these things it would run for awhile for a couple of days , but within the next couple of day's the battery is dead or it wont stay charged enough to even get it home.

Has anyone had this sort of problem or does anyone have any suggestions?

Thank you in advance.

Michele

Replace both the EEC and Fuel pump relays, they are both the same part
numbers. These relays are very problematic on these and the 1/4 ton Fords.
They stick when they go bad and can and will drain the battery overnight. I
went through this last year with my own truck, until I finally took it to a
specialty shop that figured out what the problem was.

For my own truck, there is also a TSB on the internet concerning this
problem, and I think it mentions the full size trucks in the text. Both
relays cost me around $20 a piece. Once you find them, it is a matter of
disconnecting the old relay and plugging in the new one.

Good luck
Sharky