Hummer H3. Manual — part 1425

PARK, LICENSE AND TAIL LAMPS INOPERATIVE

and Wiring Repairs .
Did you find and correct the condition?

Go to Step 13

Go to Step 11

8

Inspect for poor connections at the harness
connector of the BCM. Refer to Circuit
Testing and Wiring Repairs .
Did you find and correct the condition?

Go to Step 13

Go to Step 12

9

Repair the short to voltage in one of the
following circuits. Refer to Wiring
Repairs :

The park lamp supply voltage

The tail lamp supply voltage

The license lamp supply voltage

The marker lamp supply voltage

Did you complete the repair?

Go to Step 13

-

10

Replace the park lamp relay. Refer to
Relay Replacement (Attached to Wire
Harness) or Relay Replacement (Within
an Electrical Center) .
Did you complete the repair?

Go to Step 13

-

11

Replace the headlamp switch. Refer to
Headlamp Switch Replacement.
Did you complete the repair?

Go to Step 13

-

12

Replace the BCM. Refer to Control
Module References for replacement, setup
and programming.
Did you complete the replacement?

Go to Step 13

-

13

1. Use the scan tool in order to clear any

induced DTCs.

2. Operate the system in order to verify

the repair.

Did you correct the condition?

System OK

Go to Step 3

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

Park, License and Tail Lamps Inoperative

Step

Action

Yes

No

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

1

Did you perform the Diagnostic System
Check - Vehicle?

Go to Step 2

Go to

Diagnostic

System Check -

Vehicle

2

Verify that the park, license and tail lamps
are inoperative.
Do the park, license and tail lamps operate
normally?

Go to Testing

for Intermittent

Conditions and

Poor

Connections

Go to Step 3

3

1. Remove the park lamp relay. Refer to

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

2. Ensure that the headlamp switch is in

the ON position.

3. Test for a ground signal at the park

lamp relay control circuit terminal in
the underhood fuse block. Refer to
Circuit Testing and Electrical
Center Identification Views .

Was a ground signal present?

Go to Step 8

Go to Step 4

4

Use the scan tool to check the body control
module (BCM) park lamp switch input
data.
Does the scan tool indicate a park lamps
ON request signal?

Go to Step 7

Go to Step 5

5

Test for an open or high resistance in the
park lamp switch on signal circuit. Refer to
Circuit Testing and Wiring Repairs .
Did you find and correct the condition?

Go to Step 11

Go to Step 6

Inspect for poor connections at the harness

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

POSITION LAMPS MALFUNCTION

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Strategy Based Diagnosis

Diagnostic Procedure Instructions

Circuit/System Description

The underhood fuse block supplies battery voltage through the FRT POS fuse to the coil and
switch terminals of the FRT POSITION LMP relay located in the underhood fuse block. The

6

connector of the headlamp and panel
dimmer switch. Refer to Circuit Testing
and Wiring Repairs .
Did you find and correct the condition?

Go to Step 11

Go to Step 9

7

Inspect for poor connections at the harness
connector of the BCM. Refer to Circuit
Testing and Wiring Repairs .
Did you find and correct the condition?

Go to Step 11

Go to Step 10

8

Replace the park lamp relay. Refer to
Relay Replacement (Attached to Wire
Harness) or Relay Replacement (Within
an Electrical Center) .
Did you complete the repair?

Go to Step 11

-

9

Replace the headlamp switch. Refer to
Headlamp Switch Replacement.
Did you complete the repair?

Go to Step 11

-

10

Replace the BCM. Refer to Control
Module References for replacement,
setup and programming.
Did you complete the replacement?

Go to Step 11

-

11

1. Use the scan tool in order to clear any

induced DTCs.

2. Operate the system in order to verify

the repair.

Did you correct the condition?

System OK

Go to Step 3

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3

underhood fuse block also provides battery voltage to the PARK LP relay coil and switch
terminals. When the headlamp switch is turned to the position lamp ON position, a signal is sent
to the BCM to ground both the FRT POSITION LMP relay and PARK LP relay control circuits.
This energizes the relays, closing the switch contacts and provides battery voltage to the front and
rear position lamps. The front position lamps are permanently grounded at G105 and the rear
position lamps are grounded at G420. With both power and ground, the position lamps
illuminate. If the headlamps are activated by either the headlamp switch or the BCM in
Automatic Lamp Control (ALC) mode, just the front position lamps will be disabled.

Reference Information

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Scan Tool Reference

Scan Tool Output Controls

Scan Tool Data List

Scan Tool Data Definitions

Circuit/System Testing

1. Ignition On, observe the scan tool DRL Status data parameter while toggling the headlamp

switch between the position lamps ON and OFF positions.

If the parameter does not change between states, test the position lamps switch signal
circuit for an open, high resistance or short to ground. If the circuit tests normal, test or
replace the headlamp switch.

2. Ignition OFF, disconnect the FRT POSITION LMP relay.

3. Ignition ON, verify that a test lamp does not illuminate between the relay controlled output

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Lighting - H3