Buzzing noise from rear pick up bed on 1991 Ford Ranger

Buzzing noise coming from pick underneath the pick up bed like something electrical is running.. There is no cooling fan on the radiator... Noise would happen intermittenly when I had the heat on... Now the buzzing is constant even when the unit is off... What could it bea? don't see or notice any electrical components near transmission or converter.. help pls

by in Kissimmee, FL on December 14, 2010
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
1 answer 1 comment
ANSWER by , December 14, 2010
the only thing that i can think of in the rear of the truck is the fuel pump. when the motor goes bad, it makes a ton of noise before it fails. have it checked to confirm. Roy
COMMENT by , December 14, 2010
Thank you.. I will have it checked out