3rd Brake light problems

[NASTY04GT]

I was hoping someone could help me figure out my problem. I just put in a new 3rd brake light on my 04 GT. It never lite up and now my left and right tail lights dont flash when i hit the break. Also Cant get into gear from park. The only way to get it into gear is to turn the key over just a little then it releases it so i can put it into neutral and start it from there. Does anybody know what could be the cause of this. The only thing i researched was i could possibly be the brake switch. If so, how hard/easy is it to install?

 

[hotpony]

Well, that's pretty obvious that it's your BOO switch, or Brake On/Off, look up on the top of your brake pedal (under the dash) and you should see it. You can use a voltage meter to test out the continuity when it's released and depressed, it should change from open to closed circuit. Check that out and report back

 

[wmburns]

Did you disconnect the battery negative while doing the work? I suspect not. Further I think you have a blown fuse. There is no power to the shift interlock. That is why you can not get it into gear.

Check fuse F2.18, F2.13, F2.35, and F2.41 in the CJB. If after replacing the fuse blows again, then you have a fault.

Once the fuses have been checked good, +1 on the bad Brake switch.

As for the after market 3rd brake light, if LED check to see that the +/- is not reversed.

99-04 fuse layout.
http://www.allfordmustangs.com/foru...r-swap-wont-fire-please-help.html#post2669271

 

[evolucion311]

I vote +1 for the BO/O switch. My lights weren't working for a while and turns out my foot pulled a wire out of the switch. Had to splice it back in.

+1 on wmburns's comments, LEDs are polarity sensitive, IIRC.