i have a humming noise coming from front of truck

You could have the anti lock brake pump motor staying on, possibly due to a sticking relay.

u have got an eletrcal prblem it seems do u have electric fan or any type add on if so unplug it start truck listen for see how it turns off at this point if it solves problem u have a feed back ich gives ignition enough power to run ignition til it slows and stop feeding power back for the ign to fire add on fan that is straight wired its common

its not a fan it looks like a pump of some sort that has to do with the brakes there is 2 lines from reservoir block into this pump i unplugged it so it stopped and i drove it and it didn't change anything so i don't know