Hummer H2. Manual — part 788

5. Disconnect the park brake warning light switch. With a scan tool, observe the park brake switch

parameter. If the scan tool indicates that the park brake switch parameter is inactive, go to step 9 . If the
scan tool indicates that the park brake switch parameter is inactive, go to step 7 .

6. Disconnect the brake fluid level switch. With a scan tool, observe the brake warning light parameter. If

the scan tool indicates that the brake warning light parameter is on, go to step 10 . If the scan tool does
not indicate that the brake warning light parameter is on, go to step 8 .

7. Turn OFF the ignition. Test the signal circuit of the park brake warning light switch for a short to ground.

If the condition was found and corrected, go to step 17 . If the condition was not found and corrected, go
to step 11 .

8. Turn OFF the ignition. Test the signal circuit of the brake fluid level switch for a short to ground. If the

condition was found and corrected, go to step 17 . If the condition was not found and corrected, go to step
11 .

9. Inspect for poor connections at the harness connector of the park brake warning light switch. If the

condition was not found and corrected, go to step 17 . If the condition was not found and corrected, go to
step 13 .

10. Inspect for poor connections at the harness connector of the brake fluid level switch. If the condition was

found and corrected, go to step 17 . If the condition was not found and corrected, go to step 14 .

11. Inspect for poor connections at the harness connector of the BCM. If the condition was found and

corrected, go to step 17 . If the condition was not found and corrected, go to step 15 .

12. Inspect for poor connections at the harness connector of the instrument Panel cluster. If the condition was

found and corrected, go to step 17 . If the condition was not found and corrected, go to step 16 .

13. Replace the park brake warning light switch. See PARK BRAKE WARNING LIGHT SWITCH under

REMOVAL & INSTALLATION. If the repair was completed, go to step 17 .

14. Replace the brake fluid level switch. See MASTER CYLINDER FLUID LEVEL SENSOR under

REMOVAL & INSTALLATION. If the repair was completed, go to step 17 .

15. Replace the Body Control Module. See appropriate BODY CONTROL MODULE article in

COMMUNICATION DEVICES in ACCESSORIES & EQUIPMENT. After repairs are complete, go to
step 17 .

16. Replace the IPC. If the repair was completed, go to step 17 .

17. Operate the system in order to verify the repair. If the condition was corrected, system okay. If the

condition was not corrected, go to step 2 .

BRAKE WARNING INDICATOR INOPERATIVE

1. If the hydraulic brakes operation has been reviewed and the necessary inspection performed, go to step 2 .

If the hydraulic brakes operation has not been reviewed and the necessary inspection has not been
performed, see HYDRAULIC BRAKE SYSTEM under GENERAL DIAGNOSIS in TROUBLE
SHOOTING.

2. Turn ON the ignition, with the engine OFF. Observe the brake warning indicator. If the brake warning

indicator illuminates briefly during the bulb check, go to step 3 . If the brake warning indicator does not
illuminate briefly during the bulb check, go to step 11 .

3. Turn ON the ignition, with the engine off. Apply the park brake. If the brake warning indicator

illuminates, go to step 4 . If the brake warning indicator does not illuminate, go to step 7 .

2004 Hummer H2

2003-04 BRAKES Disc - Hummer

4. Turn OFF the ignition. Release park brake. Disconnect the brake fluid level indicator switch. Connect a

3-amp fused jumper wire between the signal circuit of the brake fluid level indicator switch and a good
ground. If the brake warning indicator illuminates, go to step 5 . If the brake warning indicator does not
illuminate, go to step 9 .

5. Inspect for poor connections or a poor ground at the brake fluid level indicator switch. If the condition

was found and corrected, go to step 17 . If the condition was not found and corrected, go to step 6 .

6. Inspect brake fluid level indicator switch for proper operation. If brake fluid level indicator switch works

properly. If brake fluid level indicator switch does not work properly, go to step 15 .

7. Disconnect the park brake warning light switch. Connect a 3-amp fused jumper wire between the signal

circuit of the park brake warning light switch and ground. If the brake warning indicator illuminated, go
to step 10 . If the brake warning indicator does not illuminate, go to step 8 .

8. Turn OFF the ignition. Disconnect the body control module. Test the signal circuit of the park brake

warning light switch for a high resistance or an open. If the condition was found and corrected, go to step
17 . If the condition was not found and corrected, go to step 12 .

9. Turn OFF the ignition. Disconnect the instrument panel cluster. Test the signal circuit of the brake fluid

level indicator switch for a high resistance or an open. If the condition was found and corrected, go to
step 17 . If the condition was not found and corrected, go to step 11 .

10. If the condition was found and corrected, go to step 17 . If the condition was not found and corrected, go

to step 11 .

11. Inspect for poor connections at the harness connector of the instrument cluster. If the condition was found

and corrected, go to step 17 . If the condition was not found and corrected, go to step 14 .

12. Inspect for poor connections at the harness connector of the Body Control Module. If the condition was

found and corrected, go to step 17 . If the condition was not found and corrected, go to step 16 .

13. Replace the park brake warning light switch. See PARK BRAKE WARNING LIGHT SWITCH under

REMOVAL & INSTALLATION. If the repair was completed, go to step 17 .

14. Replace the instrument cluster. See appropriate INSTRUMENT PANELS article in ACCESSORIES &

EQUIPMENT. If the repair was completed, go to step 17 .

15. Replace the brake fluid level indicator switch. See MASTER CYLINDER FLUID LEVEL SENSOR

under REMOVAL & INSTALLATION. If the repair was completed, go to step 17 .

16. Replace the Body Control Module. See appropriate BODY CONTROL MODULE article in

COMMUNICATION DEVICES in ACCESSORIES & EQUIPMENT. If the repair was completed, go to
step 17 .

17. Operate the system in order to verify the repair. If the condition was repaired, system okay. If the

condition was not repaired, go to step 2 .

BRAKE PULSATION

1. If you were sent here from General Diagnosis, go to next step. If you were not sent here from General

Diagnosis, see DIAGNOSTIC STARTING POINTS under TROUBLE SHOOTING.

2. Inspect the suspension system for proper operation. See appropriate SUSPENSION article. If the

condition was found and corrected, go to step 6 . If the condition was not found and corrected, go step 3 .

3. Inspect the anti-lock brake system for proper operation. See appropriate ANTI-LOCK BRAKES article.

If the condition was found and corrected, go to step 6 . If the condition was not found and corrected, go to

2004 Hummer H2

2003-04 BRAKES Disc - Hummer

step 4 .

4. Inspect the disc brake system for proper operation. See DISC BRAKE SYSTEM DIAGNOSIS under

TROUBLE SHOOTING. If the condition was found and corrected, go to step 6 . If the condition was not
found and corrected, go to step 5 .

5. Inspect the hydraulic brake system for proper operation. See HYDRAULIC BRAKE SYSTEM

DIAGNOSIS under TROUBLE SHOOTING. If the condition was found and corrected, go to step 6 . If
the condition was not found and corrected, see DIAGNOSTIC STARTING POINTS under TROUBLE
SHOOTING.

6. Road test the vehicle in order to confirm proper operation. See BRAKE SYSTEM VEHICLE ROAD

TEST under SYSTEM TESTS. If the condition is still present, go to step 2 . If the condition is not
present, system is okay.

BRAKE SYSTEM NOISE

1. If you were sent here from General Diagnosis, go to step 2 . If no, see DIAGNOSTIC STARTING

POINTS under TROUBLE SHOOTING.

2. Inspect the disc brake system for proper operation. See DISC BRAKE SYSTEM DIAGNOSIS under

TROUBLE SHOOTING. If the condition was found and corrected, go to step 6 . If the condition was not
found and corrected, go to step 3 .

3. Inspect the brake assist system for proper operation. If the condition was found and corrected, go to step

6 . If the condition was not found and corrected, go to step 4 .

4. Inspect the hydraulic brake system for proper operation. See HYDRAULIC BRAKE SYSTEM

DIAGNOSIS under TROUBLE SHOOTING. If the condition was found and corrected, go to step 6 . If
the condition was not found and corrected, go to step 5 .

5. Inspect the park brake system for proper operation. See PARK BRAKE SYSTEM DIAGNOSIS under

TROUBLE SHOOTING. If the condition was found and corrected, go to step 6 . If the condition was not
found and corrected, go to DIAGNOSTIC STARTING POINTS under TROUBLE SHOOTING.

6. Road test the vehicle in order to confirm proper operation. If the condition still present, go to step 2 . If

the condition is not present, system is okay.

BRAKING ACTION UNEVEN - PULLS TO ONE SIDE

1. If you were sent here from General Diagnosis, go to next step. If you were not sent here from General

Diagnosis, see DIAGNOSTIC STARTING POINTS under TROUBLE SHOOTING.

2. Inspect the suspension system for proper operation. See appropriate SUSPENSION article. If the

condition was found and corrected, go to step 6 . If the condition was not found and corrected, go to step
3 .

3. Inspect the steering system for proper operation. See appropriate POWER RECIRCULATING BALL

article. If the condition was found and corrected, go to step 6 . If the condition was not found and
corrected, go to step 4 .

4. Inspect the hydraulic brake system for proper operation. See HYDRAULIC BRAKE SYSTEM

DIAGNOSIS under TROUBLE SHOOTING. If the condition was found and corrected, go to step 6 . If
the condition was not found and corrected, go to step 5 .

5. Inspect the disc brake system for proper operation. See DISC BRAKE SYSTEM DIAGNOSIS under

2004 Hummer H2

2003-04 BRAKES Disc - Hummer

TROUBLE SHOOTING. If the condition was found and corrected, go to step 6 . If the condition was not
found and corrected, see DIAGNOSTIC STARTING POINTS under TROUBLE SHOOTING.

6. Road test the vehicle in order to confirm proper operation. If the condition is still present, go to step 2 . If

the condition is not present, system is okay.

BRAKING ACTION UNEVEN - FRONT TO REAR

1. If you were sent here from General Diagnosis, go to step 2 . If no, see DIAGNOSTIC STARTING

POINTS under TROUBLE SHOOTING.

2. Inspect the suspension system for proper operation. See appropriate SUSPENSION article. If the

condition was found and corrected, go to step 6 . If the condition was not found and corrected, go to step
3 .

3. Inspect the hydraulic brake system for proper operation. See HYDRAULIC BRAKE SYSTEM

DIAGNOSIS under TROUBLE SHOOTING. If the condition was found and corrected, got step 6 . If the
condition was not found and corrected, go to step 4 .

4. Inspect the disc brake system for proper operation. See DISC BRAKE SYSTEM DIAGNOSIS under

TROUBLE SHOOTING. If the condition was found and corrected, go to step 6 . If the condition was not
found and corrected, go to step 5 .

5. Inspect the brake assist system for proper operation. If the condition was found and corrected, go to step

6 . If the condition was not found and corrected, go to DIAGNOSTIC STARTING POINTS under
TROUBLESHOOTING.

6. Road test the vehicle in order to confirm proper operation. See BRAKE SYSTEM VEHICLE ROAD

TEST under SYSTEM TESTS. If the condition is still present, go to step 2 . If the condition is not
present, system is okay.

BRAKE PEDAL EXCESSIVE TRAVEL

1. If you sent here from General Diagnosis, go to next step. If you were not, sent here from General

Diagnosis see, DIAGNOSTIC STARTING POINTS under TROUBLE SHOOTING.

2. Inspect for proper brake pedal travel. See BRAKE PEDAL TRAVEL MEASUREMENT &

INSPECTION under ADJUSTMENTS & INSPECTION. If the brake pedal travel distance is within the
acceptable level, go to step 5 . If the brake pedal travel distance is not within the acceptable, go to step 3 .

3. Inspect for worn, missing or damaged brake pedal system components. Replace the brake pedal system

components that are worn, missing or damaged. See BRAKE PEDAL ASSEMBLY or BRAKE
BOOSTER under REMOVAL & INSTALLATION. If any worn, missing or damaged brake pedal
system components are found and replaced, go to step 4 . If any worn, missing or damaged brake pedal
system components were not found and replaced, go to step 5 .

4. Reinspect for proper brake pedal travel. See BRAKE PEDAL TRAVEL MEASUREMENT &

INSPECTION under ADJUSTMENTS & INSPECTION. If the brake pedal travel distance is within the
acceptable level, go to step 8 . If the brake pedal travel distance is not within the acceptable level, go to
step 5 .

5. Inspect the hydraulic brake system for proper operation. See HYDRAULIC BRAKE SYSTEM

DIAGNOSIS under TROUBLE SHOOTING. If the condition was found and corrected, go to step 8 . If
the condition was not found and corrected, go to step 6 .

2004 Hummer H2

2003-04 BRAKES Disc - Hummer