Brake Lamps

NOTE:

The brake lamps and the Center High Mounted Stop Lamp (CHMSL) are illuminated by several Light-Emitting Diode (LED) units that are soldered to the electronic circuit board within the lamp housing. The CHMSL is hard wired to the output of the brake lamp switch, while the brake lamps are powered by high side drivers within the TIPM based upon an input from the brake lamp switch. If the brake lamps and all of the LED units within the CHMSL fail to operate, diagnose and repair the brake lamps before attempting to repair the CHMSL. If the brake lamps operate but none of the CHMSL LED units illuminate, test and repair the CHMSL ground or feed circuit if required. If some of the CHMSL LED units operate and others do not, the CHMSL assembly must be replaced with a new unit.

CONDITION	POSSIBLE CAUSES	CORRECTION
BRAKE LAMP DOES NOT ILLUMINATE	1. Ineffective ground circuit.	1. Test and repair open brake lamp ground circuit if required.
	2. Ineffective fuse.	2. Test and replace the fuse in the TIPM if required.
	3. Ineffective feed circuit.	3. Test and repair open brake lamp switch output circuit or stop lamp output circuit if required.
	4. Ineffective switch.	4. Test and replace brake lamp switch if required.
	5. Ineffective TIPM inputs or outputs.	5. Use a diagnostic scan tool to test the TIPM inputs and outputs. Refer to the appropriate diagnostic information.
BRAKE LAMP DOES NOT EXTINGUISH	1. Ineffective feed circuit.	1. Test and repair shorted brake lamp switch output circuit or stop lamp output circuit if required.
	2. Improperly adjusted switch.	2. Adjust the brake lamp switch if required.
	3. Ineffective switch.	3. Test and replace brake lamp switch if required.
	4. Ineffective TIPM inputs or outputs.	4. Use a diagnostic scan tool to test the TIPM inputs and outputs. Refer to the appropriate diagnostic information.