Hummer H3. Manual — part 1548

Inside Rearview Mirror Schematics

Connector End View Reference

Mirror Connector End Views

Description and Operation

Automatic Day-Night Mirror Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Circuit/System Verification

1. Ignition ON, headlamps ON, vehicle in PARK, cover the front light sensor with a towel or

other suitable item. Shine a flashlight at the rear light sensor while observing the inside
rearview mirror face. The inside rearview mirror face should dim.

If the mirror face does not dim, refer to Inside Rearview Mirror Circuit Malfunction
under Circuit/System Testing.

2. Headlamps ON, park brake applied, cover the front light sensor with a towel or other

suitable item. Shine a flashlight at the rear light sensor while observing the inside rearview
mirror face. Place the transmission in REVERSE. The inside rearview mirror face should
transition from dim to bright.

If the mirror does not transition from dim to bright, refer to Reverse Input Malfunction
in Circuit/System Testing.

3. Remove the towel from the inside rearview mirror and remove the flashlight. Verify the

inside rearview mirror face returns to its normal bright state.

If the mirror face does not return to its normal state, test or replace the inside rearview
mirror.

Circuit/System Testing

Inside Rearview Mirror Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Mirrors - H3

2. Ignition OFF, test for less than 1 ohm of resistance between the ground circuit terminal 8

and ground.

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

3. Ignition ON, verify a test lamp illuminates between the ignition circuit terminal 13 and

ground.

If the test lamp does not illuminate, test the ignition circuit for a short to ground or an
open/high resistance.

4. If all circuits test normal, test or replace the inside rearview mirror.

Reverse Input Malfunction

1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.

2. Ignition ON, park brake applied, vehicle in REVERSE, test for B+ between the supply

voltage circuit terminal 9 and ground.

If less than the specified value, test the supply voltage circuit for a short to ground or
an open/high resistance. If the circuit tests normal, refer to Backup Lamps
Inoperative .

3. If all circuits test normal, test or replace the inside rearview mirror.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Inside Rearview Mirror Replacement

POWER MIRRORS INOPERATIVE

Diagnostic Instructions

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

Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Power Mirrors Inoperative

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

Ignition Voltage

1

1

-

-

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Mirrors - H3

Circuit/System Description

The outside rearview mirror switch controls the outside rearview mirrors based on the position of
the mirror selector switch and which movement position is selected. The outside rearview mirror
switch has four positions: up, down, left and right. Ignition voltage is applied to the switch via the
body control module (BCM) and when a movement position switch is selected, voltage is sent to
the commanded mirror via a mirror control control. The opposite mirror control circuit acts as a
ground circuit for the bi-directional mirror motor. Ground is the applied through the switch.

Reference Information

Schematic Reference

Outside Rearview Mirror Schematics

Connector End View Reference

Mirror Connector End Views

Description and Operation

Outside Mirror Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Circuit/System Verification

Mirror Motor Right Control

3

3

3

-

Mirror Motor Left Control

2, 3

2, 3

2, 3

-

Mirror Motor Up Control

2

2

2

-

Ground

1

1

-

-

1. All power mirror functions inoperative
2. Mirror vertical controls inoperative
3. Mirror horizontal controls inoperative

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Mirrors - H3

1. Ignition ON, with the mirror selector switch in the DRIVER position, command the mirrors

UP, DOWN, LEFT and RIGHT using the mirror directional switch. The driver mirror
should move in the commanded direction.

2. With the mirror selector switch in the PASSENGER position, command the mirrors UP,

DOWN, LEFT and RIGHT using the mirror directional switch. The passenger mirror
should move in the commanded direction.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the outside rearview mirror switch.

2. Ignition OFF, test for less than 2 ohms of resistance between the ground circuit terminal 2

and ground.

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

3. Ignition ON, verify a test lamp illuminates between the ignition voltage circuit terminal 1

and ground.

If the test lamp does not illuminate, test the B+ circuit for a short to ground or an
open/high resistance. If the circuit tests normal, replace the BCM.

4. Ignition OFF, reconnect the harness connector at the outside rearview mirror switch.

Disconnect the harness connector at the inoperative mirror.

5. Ignition OFF, with the outside rearview mirror switch in the UP position, test for 5 ohms of

resistance between the control circuit terminal 2 and ground.

If greater than the specified range, test the control circuit for an open/high resistance.
If the circuit tests normal, test or replace the outside rearview mirror switch.

6. With the outside rearview mirror switch in the DOWN position, test for 5 ohms of

resistance between the control circuit terminal 4 and ground.

If greater than the specified range, test the control circuit for an open/high resistance.
If the circuit tests normal, test or replace the outside rearview mirror switch.

7. With the outside rearview mirror switch in the LEFT position, test for 5 ohms of resistance

between the control circuit terminal 1 and ground.

If greater than the specified range, test the control circuit for an open/high resistance.
If the circuit tests normal, test or replace the outside rearview mirror switch.

8. With the outside rearview mirror switch in the RIGHT position, test for 5 ohms of resistance

between the control circuit terminal 2 and ground.

If greater than the specified range, test the control circuit for an open/high resistance.
If the circuit tests normal, test or replace the outside rearview mirror switch.

9. Ignition ON, with the outside rearview mirror switch in the UP position, verify a test lamp

illuminates between the control circuit terminal 4 and ground.

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Mirrors - H3