2004 SES 24V Duratech with spoiler. Parking and directionals work, but no brake light either side. Eye level brake light in spoiler does come on. Checked the fuse for "stop light" (fuse #17 if that's Ford's definition of brake lights) was OK. I'm figuring brake light switch on the brake pedal, but as I said, the light on the spoiler works and I'd think it would run through the same switch as the tail brake lights. Checked plugs and grounds both tight to each light.

Any ideas?

Thanks.

 

The 3rd brake light has another source for its current other than the stop light switch. Check for current going to and out of switch. If no current coming out, replace switch.

 

The problem ended up being the emergency 4 wayflasher button was stuck half way out.

 

Thanks for the update..

 

I have a 2004 Excursion 6.0 Powerstroke that I purchased a few weeks ago. Tonight I was driving behind my wife, who was driving the Excursion, and I noticed the brake lights didn't work (now I'm not sure if they've ever worked since I bought it). When I got home, I checked every fuse that had "brake" in the description. None of the fuses I checked were bad. All of the other lights (turn, running lights, etc.) are working fine. The Ex has 3 brake lights (one on the top of the rear glass). I've read some places about a stop light switch. Could this be the problem? Any other things to check. If I plug in a trailer tomorrow and the brake lights on the trailer work or don't work, does that help diagnose the problem? We are supposed to leave for vacation tomorrow, and I'd really like to have brake lights!! HELP!! THANKS!