Hummer H2. Manual — part 434

power window up relay ON and OFF.

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

Go to Step 8

Go to Step 5

5

Does the test lamp remain illuminated with each
command?

Go to Step 7

Go to Step 6

6

Test the control circuit of the left rear power
window up relay for a short to voltage. Refer to
Circuit Testing and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 9

7

Test the control circuit of the left rear power
window up relay for a short to ground. Refer to
Circuit Testing and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 9

8

Inspect for poor connections at the left rear power
window switch. Refer to Testing for Intermittent
Conditions and Poor Connections and Connector
Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 11

9

Inspect for poor connections at the harness
connector of the Body Control Module. Refer to
Testing for Intermittent Conditions and Poor
Connections and Connector Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 12

10

Repair the open or short to ground in the battery
positive voltage circuit of the left rear power
window switch. Refer to Wiring Repairs in Wiring
Systems.
Did you complete the repair?

Go to Step 13

-

11

Replace the left rear power window switch.
Did you complete the replacement?

Go to Step 13

-

12

Replace the Body Control Module. Refer to Body
Control Module Replacement in Body Control
System.Did you complete the replacement?

IMPORTANT:

Perform the set up procedure for the Body
Control Module.

Go to Step 13

-

13

1. Use the scan tool in order to clear the DTCs.

2. Operate the vehicle within the Conditions for

Running the DTC as specified in the
supporting text.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Doors - Hummer H2

DTC B3820

Circuit Description

The Body Control Module (BCM) grounds the control side of the left rear power window down relay upon
receiving a class 2 message from the Driver Door Module (DDM).

Conditions for Running the DTC

z

Battery voltage is between 9.0 and 16 volts.

z

The BCM has received a class 2 message from the DDM and has grounded the left rear power window
down relay control circuit.

Conditions for Setting the DTC

z

When the BCM has grounded the left rear power window down relay control circuit and the control
circuit is shorted to battery positive voltage.

z

The above condition is met for 250 milliseconds.

Action Taken When the DTC Sets

The left rear power window will be inoperative from both the driver and left rear power window switches.

Conditions for Clearing the DTC

When the fault is no longer present, the BCM changes the current DTC to a history DTC. The BCM will clear
the history DTC after 50 fault free ignition cycles.

Test Description

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

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

3: Tests for voltage at the coil side of the left rear power window down relay.

4: Verifies that the BCM is providing ground to the left rear power window down relay.

5: Tests if ground is constantly being applied to the left rear power window down relay.

DTC B3820

Does the DTC reset?

Go to Step 2

System OK

Step

Action

Yes

No

Schematic Reference: Power Window Schematics
Connector End View Reference:Power Door Systems Connector End Views

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Doors - Hummer H2

1

Did you perform the Door Systems Diagnostic
System Check?

Go to Step 2

Go to Diagnostic

System Check -

Door Systems

2

1. Install a scan tool.

2. Turn ON the ignition, with the engine OFF.

3. With a scan tool, command the left rear

power window down relay ON and OFF.

Does the left rear power window up relay turn ON
and OFF with each command?

Go to Testing for

Intermittent Conditions

and Poor Connections in

Wiring Systems

Go to Step 3

3

1. Turn OFF the ignition.

2. Disconnect the left rear power window

switch.

3. Turn ON the ignition, with the engine OFF.

4. Probe the battery positive voltage circuit of

the left rear power window switch with a test
lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 10

4

1. Connect a test lamp between the control

circuit of the left rear power window down
relay and the battery positive voltage circuit
of the left rear power window switch.

2. With a scan tool, command the left rear

power window down relay ON and OFF.

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

Go to Step 8

Go to Step 5

5

Does the test lamp remain illuminated with each
command?

Go to Step 7

Go to Step 6

6

Test the control circuit of the left rear power
window down relay for a short to voltage. Refer to
Circuit Testing and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 9

7

Test the control circuit of the left rear power
window down relay for a short to ground. Refer to
Circuit Testing and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 9

8

Inspect for poor connections at the left rear power
window switch. Refer to Testing for Intermittent
Conditions and Poor Connections and Connector

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Doors - Hummer H2

DTC B3821

Circuit Description

Battery positive voltage is supplied to the left rear power window switch and the up and down relays through
the window lockout signal circuit. If the window lockout function is disabled, the BCM supplies battery
positive voltage to the switch and relays and the left rear window operates normally. If the window lockout
function is enabled, the BCM will not supply battery positive voltage to the switch and relays and the left rear
window will be inoperative unless it is operated from the driver power window switch.

Conditions for Running the DTC

z

Battery voltage is between 9.0 and 16.0 volts.

z

The window lockout function is disabled

Conditions for Setting the DTC

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

Go to Step 13

Go to Step 11

9

Inspect for poor connections at the harness
connector of the Body Control Module. Refer to
Testing for Intermittent Conditions and Poor
Connections and Connector Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 12

10

Repair the open or short to ground in the battery
positive voltage circuit of the left rear power
window switch. Refer to Wiring Repairs in Wiring
Systems.
Did you complete the repair?

Go to Step 13

-

11

Replace the left rear power window switch.
Did you complete the replacement?

Go to Step 13

-

12

Replace the Body Control Module. Refer to Body
Control Module Replacement in Body Control
System.Did you complete the replacement?

IMPORTANT:

Perform the set up procedure for the Body
Control Module.

Go to Step 13

-

13

1. Use the scan tool in order to clear the DTCs.

2. Operate the vehicle within the Conditions for

Running the DTC as specified in the
supporting text.

Does the DTC reset?

Go to Step 2

System OK

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Doors - Hummer H2