[dangle]

check fuse? not tryin to be a smartass but i had the same problem and sure enough the fuse was blown.

 

[S0UTS]

Fuse or bulbs probably. Have you modified anything with the electrical system lately?

 

[Trap_Shooter]

No I just bought the truck last month and I noticed my reverse lights were not working, thanks guys for your help.

 

[Shibbyutman]

if its an auto (like your sig says) the pressure switch on the trans has shat the bed.