backup lights dont work
 

backup lights sporadically blow #28 fuse in 2001 f350. Help?

Brake Shift Interlock, DRL Relay Coil,
Speed Control Module, Backup Lamps,
Trailer Tow Backup Lamp Relay Coil,
Electronic Shift On The Fly Hub Lock
Solenoid, Vacuum Pump Motor

If you have 4x4, I'd check to see if it's working. Water in an electric vacume pump can cause shorts. You might also try pulling Relay 38 under the hood, to isolate it from the circuit.

Hang on a second....I'm NOT an expert but have you checked the bulb socket? How about the wiring? ReAX may be right but I was always taught to check the simple things before you start tearing into things.