Possible Causes

Circuit (G/V) open
Circuit (GY/L) short to ground
Parking brake switch
ABS module
Instrument cluster

CAUTION:

Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.

BRAKE WARNING INDICATOR IS ALWAYS ON - PINPOINT TEST REFERENCE

PINPOINT TEST 28		BRAKE WARNING INDICATOR IS ALWAYS ON
STEP	INSPECTION		ACTION
1	CARRY OUT THE INSTRUMENT CLUSTER INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL Key ON. Enter the following diagnostic mode on the scan tool: Instrument Cluster Active Command Select the instrument cluster indicator lamp control active command. Select the brake warning indicator active command on then off again. Observe the brake warning indicator. Does the brake warning indicator turn off when commanded off?	Yes	Go to next step.
1		No	Go to step 9.
2	RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND ABS MODULE SELF-TESTS Retrieve the recorded DTCs from the ABS module continuous and on-demand self-tests. Are any DTCs present?	Yes	See ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX , .
2		No	Go to next step.
3	DETERMINE THE CONDITION Key ON. Enter the following diagnostic mode on the scan tool: Instrument Cluster PIDs Apply and release the parking brake while monitoring the instrument cluster parking brake switch PID PRKSWAPPL. Do the PIDs agree?	Yes	Go to step 6.
3		No	Go to next step.
4	CHECK THE PARKING BRAKE SWITCH Key OFF. Disconnect: Parking brake switch 0918-201. Key ON. Observe the parking brake indicator. Did the brake warning indicator turn off?	Yes	INSTALL a new parking brake switch. TEST the system for normal operation.
4		No	Go to next step.
5	CHECK CIRCUIT (GY/L) FOR A SHORT TO GROUND Key OFF. Disconnect: Instrument cluster 0922-101. Measure the resistance between the parking brake switch 0918-201 pin 1, circuit (GY/L), harness side and ground. Is the resistance greater than 10,000 ohms?	Yes	Go to step 9.
5		No	Repair the circuit. Test the system for normal operation.
6	CHECK THE ABS MODULE OPERATION Key OFF. Disconnect: ABS module 0413-102. Connect a fused (5A) jumper wire between the ABS module 0413-102 pin 27, circuit (G/V), harness side and ground. Key ON. Observe the brake warning indicator. Does the brake warning indicator turn off after prove-out?	Yes	Remove the jumper wire. Go to step 8.
6		No	Remove the jumper wire. Go to next step.
7	CHECK CIRCUIT (G/V) FOR AN OPEN Key OFF. Disconnect: Instrument cluster 0922-101. Measure the resistance between the ABS module 0413-102 pin 27, circuit (G/V), harness side and the instrument cluster 0922-101 pin 16, circuit (G/V), harness side. Is the resistance less than 5 ohms?	Yes	Go to step 9
7		No	Repair circuit (G/Y) for an open. Test the system for normal operation.
8	CHECK FOR CORRECT ABS MODULE OPERATION Disconnect the ABS module connector. Check for: corrosion damaged pins pushed-out pins Connect the ABS module connector and make sure it seats correctly. Operate the system and verify the concern is still present. Is the concern still present?	Yes	Install a new ABS module. see ANTI-LOCK BRAKE SYSTEM (ABS) MODULE . Test the system for normal operation.
8		No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. Clear the DTCs. Repeat the self-test.
9	CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION Disconnect all the instrument cluster connectors. Check for: corrosion damaged pins pushed-out pins Connect all the instrument cluster connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present?	Yes	Install a new instrument cluster. see INSTRUMENT CLUSTER . Test the system for normal operation.
9		No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.