Hummer H3. Manual — part 1653

Test Description

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

2: This step tests for the possibility of a missing system input or a system fault.

3: This step tests for a missing PRNDL input from the transmission.

4: This step tests for a missing VSS signal from the ABS system.

5: This step determines if the condition is caused by a faulty encoder motor or a mechanical
internal fault to the transfer case.

Transfer Case Shift Control Switch Indicator Flashes, then Returns to Previous Mode

Step

Action

Yes

No

Schematic Reference: Transfer Case Control Schematics
Connector End View Reference: Transfer Case Control Connector End Views

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. Place the vehicle in Neutral.

3. Select a different mode on the transfer

case shift control switch.

Does the switch flash the full 15 seconds?

Go to Step 3

Go to Step 5

3

1. Connect a scan tool to the vehicle.

2. Test for transmission DTCs indicating

loss of the PRNDL signal.

Is a DTC set?

Go to
Diagnostic
Trouble Code
(DTC) List -
Vehicle

Go to Step 4

4

With the scan tool, test for ABS DTCs
indicating a loss of VSS.
Is a DTC set?

Go to
Diagnostic
Trouble Code
(DTC) List -
Vehicle

Go to Testing
for
Intermittent
Conditions
and Poor
Connections

1. Remove the transfer case encoder

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3

TRANSFER CASE SHIFT CONTROL SWITCH INDICATOR INOPERATIVE - ONE OR MORE

Circuit Description

The indicator lamps circuit consist of the following 5 individual lamps contained inside the
mode/range switch assembly:

4HI

4HI Lock

4LO Lock

Differential Lock

Neutral

The following lamps are contained inside the respective mode button for each lamp:

4HI

4HI Lock

5

motor, while leaving the electrical
harness connected.

2. Attempt to shift the transfer case to a

different mode.

Is the encoder motor able to make the shift?

Go to Step 7

Go to Step 6

6

Replace the transfer case encoder motor.
Refer to Transfer Case Motor/Encoder
Replacement.
Is the repair complete?

Go to Step 8

-

7

Remove the transfer case and repair, for a
shift detent lever shaft binding condition.
Refer to Transfer Case Disassemble.
Is the repair complete?

Go to Step 8

-

8

1. Use the scan tool in order to clear the

DTCs.

2. Operate the vehicle in order to

determine if the symptom has been
corrected.

Is the symptom still present?

-

System OK

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3

4LO Lock

Differential Lock

When the ignition is ON, the transfer case shift control module illuminates the indicator lamp that
corresponds to the current automatic transfer case (ATC) gear position by providing a ground
through a current limiting driver.

The transfer case shift control module flashes each indicator lamp after a shift has been requested
and will continue to flash until the transfer case shift control module can complete the shift.

A solid state circuit located inside the switch supplies ignition voltage to the lamps. The solid
state circuit also receives voltage whenever the headlamp switch is in the parklamp or headlamp
position. When the solid state circuit receives voltage from the headlamp switch it will reduce the
voltage that it supplies to the indicator lamps, dimming the lamps when the headlamps are ON.

Test Description

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

2: This step determines if the module can command the indicators ON.

3: This step determines if the indicator or wiring is at fault.

4: This step tests the lamp feed circuit for an open or high resistance.

5: This step tests the LED dimming circuit for an open or short to ground.

Transfer Case Shift Control Switch Indicator Inoperative - One or More

Step

Action

Yes

No

Schematic Reference: Transfer Case Control Schematics
Connector End View Reference: Transfer Case Control Connector End Views

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. Install a scan tool.

3. Use the scan tool in order to

command all the indicator lamps
ON.

Go to Testing
for Intermittent
Conditions and

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3

SERVICE INDICATOR ALWAYS ON

Do all the lamps turn ON?

Poor
Connections

Go to Step 3

3

1. Access the back of the mode switch.

2. Using a fused jumper back probe the

effected indicator control circuit to
ground.

Does the effected lamp turn ON?

IMPORTANT:

Do not damage a connector or circuit when
back probing.

Go to Step 4

Go to Step 5

4

Test the effected indicator control circuit
for an open or high resistance. Refer to
Circuit Testing and Wiring Repairs .
Was the condition found and corrected?

Go to Step 8

Go to Step 7

5

Test the LED dimming circuit for an open
or short to ground. Refer to Circuit
Testing and Wiring Repairs .
Was the condition found and corrected?

Go to Step 8

Go to Step 6

6

Replace the mode switch. Refer to
Transfer Case Shift Control Switch
Replacement.
Is the repair complete?

Go to Step 8

-

7

Replace the transfer case shift control
module. Refer to Control Module
References for replacement, setup and
programming.
Is the repair complete?

Go to Step 8

-

8

1. Use the scan tool in order to clear

the DTCs.

2. Operate the vehicle in order to

determine if the symptom has been
corrected.

Is the symptom still present?

Go to Step 2

System OK

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3