GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Door Lock/Indicator Schematics

Connector End View Reference: Power Door Systems Connector End Views or Body Rear End Connector End Views in Body Rear End

1

Did you perform the Door Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Door Systems

2

Activate the door lock switches to the lock and unlock positions.

Does the rear lift gate lock actuator lock and unlock?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Disconnect the lift gate lock actuator.
  2. With a test lamp connected to a good ground, probe the door lock actuator lock circuit at the door lock actuator harness connector.
  3. Activate a door lock switch to lock position.

Does the test lamp illuminate?

Go to Step 4

Go to Step 6

4

  1. With a test lamp connected to a good ground, probe the door lock actuator unlock circuit at the door lock actuator harness connector.
  2. Activate a door lock switch to unlock position.

Does the test lamp illuminate?

Go to Step 5

Go to Step 7

5

  1. Connect a test lamp between the door lock actuator lock and unlock circuits at the door lock actuator harness connector.
  2. Activate a door lock switch to both the lock and unlock positions.

Does the test lamp illuminate in both positions?

Go to Step 9

Go to Step 8

6

Test for an open or short to ground in the door lock actuator lock circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 8

7

Test for an open or short to ground in the door lock actuator unlock circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 8

8

Inspect for poor connections at the harness connector of the lift gate 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 12

Go to Step 10

9

Inspect for poor connections at the harness connector of the door 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 12

Go to Step 11

10

Important: Perform the set up procedure for the lift gate module.

Replace the lift gate module. Refer to Liftgate Control Module Replacement in Body Rear End.

Did you complete the repair?

Go to Step 12

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11

Replace the appropriate door lock actuator. Refer to Front Side Door Lock Actuator Replacement .

Did you complete the repair?

Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2