Hummer H2. Manual - part 2142

Circuit Description 

If the vehicle is equipped with a floor mounted console gearshift, an ignition lock cylinder control actuator 
system is used in the steering column. The purpose of the system is to prevent the ignition lock cylinder from 
being turned to the lock position while the transmission is in gear, this also prevents the steering wheel from 
being locked. The system consists of an ignition lock cylinder actuator and a park position switch. The actuator 
contains a pin that is spring loaded out, to prevent the ignition lock cylinder from being turned to the lock 
position when the gearshift is not in Park. The park position switch is located in the floor mounted gearshift 
assembly, as part of the automatic transmission shift lock control switch. The switch is closed with the gearshift 
in PARK, and open in all other positions 

System Operation 

When the gearshift is in the PARK position, the park position switch is closed. This applies voltage to the 
ignition lock cylinder actuator and the pin retracts, allowing the ignition lock cylinder to be turned to the LOCK 
position. When the gearshift is not in PARK, the park position switch is open. No voltage is applied to the 
ignition lock cylinder actuator and the spring loaded pin remains in the out position, preventing the ignition lock 
cylinder from being turned to LOCK. If vehicle power is lost while the ignition lock cylinder is not in the 
LOCK position, the system will prevent the operator from turning the ignition key to the lock position or 
removing the key. If the vehicle has lost power, pushing the ignition lock cylinder release button on the 
underside of the ignition lock cylinder will override the system and allow the key to be removed. 

Ignition Can/Cannot Be Turned Off with Transmission in Any Gear 

Step

Action

Yes

No

Schematic Reference:Column/Ignition Lock Schematics 
Connector End View Reference:Steering Wheel and Column Connector End Views

1

Verify the fault is present. 
Does the system operate normally?

Go to Testing for 

Intermittent 

Conditions and Poor 

Connections in Wiring 

Systems

Go to Step 2

2

Does the automatic transaxle shift lever 
operate normally?

Go to Step 3

Go to Diagnostic Starting 

Point - Automatic 

Transmission Shift Lock 

Control in Shift Lock 

Control

3

1. Push the ignition lock cylinder control 

actuator release button which is on the 
underside of the ignition lock 
cylinder.  

2. Turn the key to the LOCK position 

and remove the key.  

Were you able to turn the key to the LOCK 
position and remove the key?

Go to Step 4

Go to Lock System Does 

Not Lock

1. Turn OFF the ignition.  

 

2004 Hummer H2 

2004 STEERING Steering Wheel and Column - Hummer H2

  

4

2. Disconnect the ignition lock cylinder 

control actuator.  

3. Connect a test lamp between the 

battery positive voltage and ground 
circuits of the ignition lock cylinder 
control actuator.  

4. Turn ON the ignition, with the engine 

OFF.  

5. Cycle the gear shift from Park to 

Drive.  

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

Go to Step 11

Go to Step 5

5

Does the test lamp remain illuminated with 
each cycle?

Go to Step 8

Go to Step 6

6

Connect a test lamp between the ground 
circuit of the ignition lock cylinder control 
actuator and B+ voltage. 
Does the test lamp illuminate?

Go to Step 7

Go to Step 9

7

Test the control circuit of the ignition lock 
cylinder control actuator for an open. Refer 
to Circuit Testing and to Wiring Repairs 
in Wiring Systems. 
Did you find and correct the condition?

Go to Step 14

Go to Step 10

8

Test the control circuit of the ignition lock 
cylinder control actuator for a short to 
voltage. Refer to Circuit Testing and to 
Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

Go to Step 14

Go to Step 10

9

Repair the open in the ground circuit of the 
ignition lock cylinder control actuator. Refer 
to Wiring Repairs in Wiring Systems. 
Did you complete the repair?

Go to Step 14

-

10

Inspect for poor connections at the 
automatic transmission shift lock actuator. 
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 14

Go to Step 12

11

Inspect for poor connections at the ignition 
lock cylinder control actuator. Refer to 
Testing for Intermittent Conditions and 
Poor Connections and to Connector 
Repairs in Wiring Systems. 
Did you find and correct the condition?

Go to Step 14

Go to Step 13

 

2004 Hummer H2 

2004 STEERING Steering Wheel and Column - Hummer H2

  

LOCK SYSTEM DOES NOT UNLOCK 

Lock System Does Not Unlock 

12

Replace the automatic transmission shift 
lock actuator. Refer to Automatic 
Transmission Shift Lock Actuator 
Replacement in Shift Lock Control. 
Did you complete the replacement?

Go to Step 14

-

13

Replace the ignition lock cylinder control 
actuator. Refer to Steering Wheel Theft 
Deterrent Lock Replacement . 
Did you complete the replacement?

Go to Step 14

-

14

Operate the system in order to verify the 
repair. 
Did you correct the condition?

System OK

Go to Step 2

Step

Action

Yes

No

DEFINITION: The lock system does not allow the key to rotate out of the OFF position.

1

Did you review the Steering Wheel and Column 
Description and Operation?

Go to 

Step 2

Go to Steering Wheel and 

Column Description and 

Operation

2

Verify that the lock system does not unlock. 
Does the lock system operate normally?

System 

OK

Go to Step 3

3

Inspect for an incorrect, worn, or damaged key. 
Is the key incorrect, worn, or damaged?

Go to 

Step 7

Go to Step 4

4

Inspect for a faulty lock cylinder. 
Is the lock cylinder damaged?

Go to 

Step 8

Go to Step 5

5

Inspect the ignition lock cylinder case assembly for 
looseness. 
Is the ignition lock cylinder case assembly loose?

Go to 

Step 9

Go to Step 6

6

Inspect the ignition switch assembly for damage. 
Is the ignition switch assembly damaged?

Go to 

Step 10

Go to Step 3

7

Replace the key. Refer to Key and Lock Cylinder 
Coding in General Information. 
Did you complete the repair?

Go to 

Step 11

-

8

Replace the lock cylinder. Refer to Ignition Lock 
Cylinder Replacement . 
Did you complete the repair?

Go to 

Step 11

-

9

Tighten the ignition lock cylinder case assembly. 
Refer to Fastener Tightening Specifications . 
Did you complete the repair?

Go to 

Step 11

-

10

Replace the ignition switch. Refer to Ignition 
Switch Replacement . 
Did you complete the repair?

Go to 

Step 11

-

 

2004 Hummer H2 

2004 STEERING Steering Wheel and Column - Hummer H2

  

LOCK SYSTEM DOES NOT LOCK 

Lock System Does Not Lock 

LOCK SYSTEM STICKS IN START 

Lock System Sticks in Start 

11

Operate the system in order to verify the repair. 
Did you correct the condition?

System 

OK

Go to Step 3

Step

Action

Yes

No

DEFINITION: The lock system will not allow the key to be turned to the OFF lock position.

1

Did you review the Steering Wheel and Column 
Description and Operation?

Go to 

Step 2

Go to Steering Wheel and 

Column Description and 

Operation

2

Verify that the lock system does not lock. 
Does the lock system operate normally?

System 

OK

Go to Step 3

3

Inspect for a faulty lock cylinder or release button. 
Is the lock cylinder or release button damaged?

Go to 

Step 6

Go to Step 4

4

Inspect the shift cable adjustment. 
Is the shift cable adjusted incorrectly?

Go to 

Step 7

Go to Step 5

5

Inspect the ignition switch for damage. 
Is the ignition switch damaged?

Go to 

Step 8

Go to Step 6

6

Replace the lock cylinder. Refer to Ignition Lock 
Cylinder Replacement . 
Did you complete the repair?

Go to 

Step 9

-

7

Adjust the shift cable. Refer to Automatic Transmission 
Range Selector Cable Adjustment in Automatic 
Transmission - 4L60-E/4L65-E. 
Did you complete the repair?

Go to 

Step 9

-

8

Replace the ignition switch. Refer to Ignition Switch 
Replacement . 
Did you complete the repair?

Go to 

Step 9

-

9

Operate the system in order to verify the repair. 
Did you correct the condition?

System 

OK

Go to Step 3

Step

Action

Yes

No

1

Did you review the Steering Wheel and Column 
Description and Operation?

Go to 

Step 2

Go to Steering Wheel and 

Column Description and 

Operation

2

Verify that the lock system sticks in the START 
position. 
Does the lock system operate normally?

System 

OK

Go to Step 3

3

Inspect the ignition lock cylinder case assembly for 
damage. 

Go to 

 

2004 Hummer H2 

2004 STEERING Steering Wheel and Column - Hummer H2