I have a 2006 Mustang GT that I had just bought from a dealer that has no warranty (130,000 miles) and i've been told that my brake lights arent working properly. According to what I have been told is that only my middle tail lights work when i brake and the outside ones don't work and niether does the third brake light below the spoiler. Every mustang that I have seen has a total of 5 braking lights (except 2010-14) I only have 2...which is weird. I checked my fuses behind the passenger kick panel and even checked the one under the hood and they're all fine. I havent replaced the bulbs but they all seem to be good even though all my tail lights, hazards, and turn signals work. I really need to get this fixed cause I feel out of the ordinary.

Thanks,
Ruben

 

You need to test the voltage to each light with a mutli-meter. Rent one or borrow it. Check voltage with everything off, then with the brake pedal depressed. This will tell you if the bulbs are getting power. Should be between 12 to 14 volts to each bulb with the brake pedal depressed. If you are not getting power to the bulbs, check your wire harness connections. Also check the voltage at your brake switch on the pedal. That should get you started. Need any more help let me know.

 

Any luck with your problem?

 

Wonder if you have water damage on the SJB (smart junction box)?

 

Did you try replacing the bulbs?