Ford F150 electrical problem I think!!! HELP

Sounds like you have a draw, pull 1 clamp off battery and check the amps its pulling with multimeter

Should by less then 0.5 amps

You have to wait a couple of seconds to let the interior lite etc. die down before getting reliable reading.

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

I forgot to mention, check to make sure that the harness on the alternator is not burned or melted. These alternators are notorious for shorting out and lighting on fire. The fix is to cut off the old connector and replace it with a new one from Ford.

Sharky