The best clue is the center high-mount light also does not work. That does not go through the signal switch or anything else, so the circuit is very basic. Also, all three brake lights are on separate circuits, so there is very little all three have in common. That is where we have to look.
Go to the gray/red wire on the brake light switch and check for twelve volts. It should be there all the time. If that is missing, check for twelve volts on both sides of fuse 26, a 20-amp, in the Integrated Power Module, (fuse box), under the hood.
If you do have that twelve volts at the switch, check for twelve volts on the white/tan wire when you push the brake pedal. If that is missing, the switch is defective or it is the wrong switch. Let me know what you find.
Tuesday, April 24th, 2018 AT 12:13 PM