Hummer H3. Manual — part 1706

The numbers below refer to the step numbers on the diagnostic table.

2: Listen for an audible click when the rear defog relay operates. Command both the ON
and OFF states. Repeat the commands, as necessary.

3: This step verifies that the BCM is providing battery positive voltage input to the rear
defog relay.

5: This step tests for a short to ground or short to voltage on the rear defog relay control
circuit of the rear defog relay coil.

DTC B0285 or B0286

Step

Action

Yes

No

Schematic Reference: Defogger Schematics
Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System
Check - Vehicle?

Go to Step 2

Go to
Diagnostic
System Check -
Vehicle

2

1. Turn ON the ignition, with the engine

OFF.

2. With a scan tool, select from Special

Functions the Rear Defogger Relay
output control from the body control
module (BCM) output controls menu.

3. Command the Rear Defogger Relay

ON and OFF.

Do you hear a click when you command the
Rear Defogger Relay ON and OFF?

Go to Testing
for Intermittent
Conditions and
Poor
Connections

Go to Step 3

3

1. Turn OFF the ignition.

2. Disconnect the rear defog relay.

3. Turn ON the ignition, with the engine

OFF.

4. Connect a test lamp between the rear

defog relay connector control circuit of
the rear defog relay coil and ground.

5. With a scan tool, command the rear

defog relay ON and OFF.

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Fixed and Moveable Windows - H3

Does the test lamp turn ON and OFF with
each command?

Go to Step 4

Go to Step 5

4

1. Connect a test lamp between the supply

voltage circuit of the rear defog relay
connector and the rear defog relay
control circuit.

2. With a scan tool, command the rear

defog relay ON and OFF.

Does the test lamp turn ON and OFF with
each command?

Go to Step 6

Go to Step 8

5

Test the rear defog relay control circuit and
rear defog indicator control circuit for the
following:

An open

A high resistance

A short to ground

A short to voltage

Refer to Circuit Testing and Wiring
Repairs .
Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

Inspect for poor connections at the rear
defog relay. Refer to Testing for
Intermittent Conditions and Poor
Connections and Connector 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 Testing for
Intermittent Conditions and Poor
Connections and Connector Repairs .
Did you find and correct the condition?

Go to Step 11

Go to Step 10

8

Repair an open or high resistance in the
ground circuit of the rear defog relay. Refer
to Wiring Repairs .
Did you complete the repair?

Go to Step 11

-

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Fixed and Moveable Windows - H3

SYMPTOMS - FIXED AND MOVEABLE WINDOWS

1. Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in

order to verify that all of the following are true:

There are no DTCs set.

The control modules can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions.

Refer to the following system descriptions:

Power Windows Description and Operation

Rear Window Defogger Description and Operation

Visual/Physical Inspection

Inspect for aftermarket devices which could affect the operation of the power window or
rear defogger systems. Refer to Checking Aftermarket Accessories .

Inspect the easily accessible or visible system components for obvious damage or conditions
which could cause the symptom.

9

Replace the rear defog relay. Refer to Relay
Replacement (Attached to Wire Harness)
or Relay Replacement (Within an
Electrical Center) .
Did you complete the replacement?

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 the

DTCs.

2. Operate the vehicle within the

Conditions for Setting the DTC, as
specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK

IMPORTANT: The following steps must be completed before using the symptom

tables.

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Fixed and Moveable Windows - H3

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to
Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the
symptom:

Rear Window Defogger Always On

Defogger Grid Lines Diagnosis

Rear Window Defogger Inoperative

Power Window Inoperative - Driver Door

Power Window Inoperative - Passenger Door

Power Windows Inoperative - All

Power Window Express Down Function Inoperative

Power Window Lockout Function Inoperative

REAR WINDOW DEFOGGER ALWAYS ON

Rear Window Defogger Always On

Step

Action

Yes

No

Schematic Reference: Defogger Schematics
Connector End View Reference: Window Systems 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 rear window defogger is
always ON.
Does the rear window defogger operate
normally?

Go to Testing
for Intermittent
Conditions and
Poor
Connections

Go to Step 3

3

With a scan tool, observe the Rear Defog
Switch data parameter in the Body
Control Module data list.
Does the scan tool display Inactive?

Go to Step 4

Go to Step 6

2007 Hummer H3

2007 ACCESSORIES & EQUIPMENT Fixed and Moveable Windows - H3