Fuel pump keeps running.....Help!!!!

For some unknown reason my fuel pump keeps running while the battery is hooked up without a key in the ignition. It started this about 2 days ago. It only ran for about 15 min or so but would cycle on and off all day and all night long. I ended up having to disconnect the battery when it finally stopped turning its self off. I know it is (the pump) supposed to run for 2 seconds before you move the key to the start position, but after 2 seconds the relay opens the circuit (you can hear the click) but the pump continues to run. The voltage around 12-13 volts with a starter, alternator & battery that are all less than 6 months old.



The relay is good I've checked it.
The pump continues to run with the relay removed.
All of this with the key out of the ignition.

Disconnect the fuel pump/oil pressure switch and see if it still does it. If not thats your problem.

sounds like the fuel pump relay in under hood fuse box, try finding another next to it thats the same , from the headlamp relay and swap them and see if it helps.

sounds like the fuel pump relay in under hood fuse box, try finding another next to it thats the same , from the headlamp relay and swap them and see if it helps.

If the pump runs with the relay removed, it's not the relay.

It sounds like you have a short to voltage somewhere. It is probably in the fuse box, because there are no always-hot wires run to the back of the truck, and having two hot wires both worn through and not short to ground is pretty unlikely. Start by pulling all the fuses one at a time, you may get lucky and at least find out which circuits are bad, narrowing your search a bit. Older fuse boxes will get corroded inside and bare metal touches bare metal... a real PITA to fix.

Probably a faulty oil pressure switch

Probably a faulty oil pressure switch

The oil pressure switch doesn't supply B+ to the pump, it allows the current from the relay to reach the pump.

What engine/year truck is this?

Original post is almost 5 yrs old.