I have a 2000 f150 4x4 5.4l lariat.
Ive had no problem w the lights before whether towering a trailer or not, but this weekend my brake lights were working. .. plug up my boat trailer lights and checked all lights and did not have brake lights to trailer or on truck. Tail lights and turn signals work fine. I've never had this problem before but now I dont have any brake lights on my truck at all. Rear or 3rd light. I checked around near plug on truck and all seems ok. All fuses are good under dash and under hood. Pulled brake switch and tried a jumper wire and still no brake lights. ...ANY IDEAS?

 

How did you test the fuses :
1. Pull stare at it and put it back in
or
2. Test both pins on the back of the fuse while installed

don't know why you are "checking" all the fuses, best to start with the fuse for the stop lamp switch, cab fuse panel fuse #13
- Owners Manual page 180 - in PDF form. Printed check in the Roadside emergencies section.

This the fuse that powers the BOO ( Brake On Off ) switch.
- Might be you cannot get the truck out of park once it is started, might have to put it in neutral to get it into drive at the moment ( Shift interlock actuator is also the same fuse ).

This same circuit also feeds BJB fuse #20 for the trailer tow adapter stop lamps.
- Meter check would have shown this fuse dead on both sides with CJB fuse #13 blown.

Might want to start with checking from a known good ground to both pins on the back of fuse #13 with it installed, and go from there.