so I walked out to my truck to hear what sounded like a blower motor running...with the key out of the ignition. so I pop the Hood and see this tiny blower motor on the passenger side is running. I unhooked it and drove my truck to the store. came back, popped the Hood and reconnected it, this time it was not running. I Just wonder...what is it for? never heard it run before. any ideas? this is a flat motor/blower of some kind right by the battery...first one to answer gets a free e-cookie!

 

That's for cooling the fuel rail to prevent vapor lock. Plug it back in.

 

oh ok, thank you! never heard of anything like that but hell, good way to solve a common problem. is it normal for it to run with the ignition off? never heard it before And I've been around this truck since 1991 (was my great grandpa's truck)

 

Leave it unplugged. The relay rusts, and can lock on, killing the battery. The engine will never get hot enough to vapor lock, and if it DID get that hot, vapor locking would be the best thing for it.

 

well where is the relay? I mean, if I wanted to replace it to keep it functioning?

 

Somewhere near the radiator fan, probably beside the battery. It's about the same size & shape as a MAP sensor:

 

thanks bud!