What have you tried? The only way I know how to diagnose a situation like yours is to go to each switch that controls the device not working and check the power feed to the switch first. No power, then the problem is upstream...break in the line, fuse, relay or some other source. Are those OK?....should have power. With power, check the switch for open/close. Switch OK?....then start tracing wires from switch to socket looking for breaks or grounds.
Get a multimeter and learn to use it with the wiring diagram for your year truck. If you can locate someone who actually is good at tracing electric issues, they'll likely charge you a hundred bucks an hour with a one-hour minimum. Someone who is not good, will charge the same, but cost you twice as much.