Hummer H3. Manual — part 1426

circuit and ground.

If the test lamp illuminates, test the relay controlled output circuit for a short to
voltage.

4. Verify that a test lamp illuminates between the relay coil B+ circuit and ground.

If the test lamp does not illuminate, test the relay coil B+ circuit for a short to ground
or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open,
test the relay controlled output circuit for a short to ground. If the circuit tests normal,
test or replace the front position lamp relay.

5. Verify that a test lamp illuminates between the relay switch B+ circuit and ground.

If the test lamp does not illuminate, test the relay switch B+ circuit for an open/high
resistance.

6. Disconnect the harness connector at the inoperative position lamp.

7. Test for less than 1.0 ohm of resistance between the inoperative position lamp ground circuit

terminal 1 and ground.

If greater than the specified range, test the ground circuit for an open/high resistance.

8. Connect the harness connector at the inoperative position lamp.

9. Connect a 10-A fused jumper wire between the relay switch B+ circuit and the relay

controlled output circuit. Verify the position lamps are activated.

If the position lamps do not activate, test the relay controlled output circuit for an
open/high resistance. If the circuit tests normal, test or replace the inoperative position
lamp bulb.

10. Connect a test lamp between the relay coil B+ circuit and the relay coil control circuit.

11. Command the position lamps ON and OFF with the scan tool utilizing the Daytime Running

Lamps output control. The test lamp should turn ON and OFF when changing between the
commanded states.

If the test lamp is always ON, test the relay coil control circuit for a short to ground. If
the circuit tests normal, replace the BCM.

If the test lamp is always OFF, test the relay coil control circuit for a short to voltage
or an open/high resistance. If the circuit tests normal, replace the BCM.

12. If all circuits test normal, test or replace the position lamp relay.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an
Electrical Center) .

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

Position Lamp Bulb Replacement.

Control Module References for BCM replacement, setup and programming.

STOP LAMPS ALWAYS ON

Stop Lamps Always On

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics
Connector End View Reference: Lighting Systems Connector End Views

1

Did you review the Exterior Lighting
Systems Description and Operation and
perform the necessary inspections?

Go to Step 2

Go to Exterior
Lighting
Systems
Description and
Operation

2

Verify that the stop lamps are always ON.
Do the stop lamps operate normally?

Go to Testing
for Intermittent
Conditions and
Poor
Connections

Go to Step 3

3

Disconnect the stop lamp switch.
Do the stop lamps remain illuminated?

Go to Step 4

Go to Step 5

4

Test for a short to voltage in one of the
following circuits or components. Refer to
Wiring Repairs .

Stop lamp switch signal

Center high mounted stop lamp
(CHMSL) supply voltage

Stop lamp supply voltage

Electronic brake control module
(EBCM) center high mounted stop
lamp (CHMSL) supply voltage input

Powertrain control module (PCM)
center high mounted stop lamp
(CHMSL) supply voltage input

Did you find and correct the condition?

Go to Step 7

Go to Step 6

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

STOP LAMPS INOPERATIVE

Stop Lamps Inoperative

5

Replace the stop lamp switch. Refer to
Stop Lamp Switch Replacement.
Did you complete the repair?

Go to Step 7

-

6

Replace the body control module (BCM).
Refer to Control Module References for
replacement, setup and programming.
Did you complete the repair?

Go to Step 7

-

7

Operate the system in order to verify the
repair.
Did you correct the condition?

System OK

Go to Step 3

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics
Connector End View Reference: Lighting Systems Connector End Views

1

Did you review the Exterior Lighting
Systems Description and Operation and
perform the necessary inspections?

Go to Step 2

Go to Exterior
Lighting
Systems
Description and
Operation

2

Verify that the stop lamps are inoperative.
Do the stop lamps operate normally?

Go to Testing
for Intermittent
Conditions and
Poor
Connections

Go to Step 3

3

Is only one lamp inoperative?

Go to Step 4

Go to Step 5

4

Inspect the lamp for an open filament or
poor connector terminal contact.
Was a condition found?

Go to Step 11

Go to Step 10

5

Connect a test lamp from ground to the
supply voltage circuit terminal of the
inoperative lamp socket or connector and
apply the service brake. Refer to Circuit
Testing .
Does the test lamp illuminate?

Go to Step 8

Go to Step 6

Remove the stop lamp switch and install a

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

6

fused jumper between the stop lamp switch
battery positive voltage circuit terminal
and the stop lamp switch signal circuit
terminal of the stop lamp switch connector.
Do the stop lamps illuminate?

Go to Step 12

Go to Step 7

7

Test for one of the following conditions.
Refer to Circuit Testing .

An open, high resistance or short to
ground in the battery positive voltage
circuit or the stop lamp supply
voltage circuit.

An open or high resistance in the
ground circuit.

Did you find and correct the condition?

Go to Step 14

Go to Step 9

8

Repair the open or high resistance in the
ground circuit of the inoperative lamp.
Refer to Wiring Repairs .
Is the repair complete?

Go to Step 14

-

9

Inspect for poor connections at the harness
connector of the body control module
(BCM). Refer to Testing for
Intermittent Conditions and Poor
Connections and Connector Repairs .
Did you find and correct the condition?

Go to Step 14

Go to Step 13

10

Repair one of the following conditions.
Refer to Wiring Repairs .

An open, high resistance or a short to
ground in the stop lamp supply
voltage circuit

An open or high resistance in the
ground circuit

Is the repair complete?

Go to Step 14

-

Repair the connector or replace the bulb.

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3