Confirm if the high mounted 3rd brake light works or not.
If the 3rd brake light works but the others do not, think multi-function switch.
If the 3rd brake light does not work, think brake pedal switch, trunk ground, or wiring fault.
If the 3rd brake light works but the others do not, think multi-function switch.
If the 3rd brake light does not work, think brake pedal switch, trunk ground, or wiring fault.