both backup lights are not working on my '04 F150 Screw- replaced both -still didn't work- checked fuse panel (#14 according to owner's manual)- fuse ok -need suggestions where to check now

 

When you had the taillamps out did you notice any corroding or anything in the light socket? Any cuts in the wires to them?

 

I'll make an assumption that you have two working bulbs in your lamps first. If both are out you could have a systematic problem caused by a break in the wire that feeds both D & Pass side lamps. Check on wire harness group cable from lamps back to cab. The switch that engages the backup lamps is mounted on the Transmission. The TR Switch (usually mounted to engagement lever) has been known to go bad leaving the back up lamps permanently on or never on. Check leads at transmission engagement lever for opens or splices in the insulation. A problem that is possible (but not probable) is that both backup lamp sockets are bad or have a common ground lead; which has gone open. At this stage of the game you are looking for an unexpected opening of a wire or switch; since you have checked for a fuse blowing shortage to ground.

 

The sockets & wires in the tail light module were ok. I w ill check the wiring back to the transmission-thanks for the help