GM Service Manual Online
For 1990-2009 cars only

Power Door Locks Inoperative - One Motor Liftgate

Step

Action

Value(s)

Yes

No

1

Did you review the Door Lock System operation and perform the necessary inspections?

--

Go to Step 2

Go to Power Door Locks Operation

2

Verify the fault is present.

Does the system operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Turn the ignition to the ON position.
  2. Roll down the windows.
  3. Close all of the doors.
  4. Connect a scan tool.
  5. Using the scan tool, check for any DTCs in the body control module (BCM).

Does the scan tool show any DTCs?

--

Go to Diagnostic System Check - Body Control System

Go to Step 4

4

Check that the right rear door lock operates correctly.

Does the right rear door lock operate correctly?

--

Go to Step 5

Go to Power Door Locks Inoperative - One Motor

5

  1. Disconnect the connector to the liftgate door lock actuator.
  2. Using adapter kit J 35616 , connect a test lamp between the power door unlock feed from the harness side connector and ground.
  3. Press the lock switch to the unlock position.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 7

6

  1. Using adapter kit J 35616 , connect a test lamp between the power door lock feed from the harness side connector and ground.
  2. Press the lock switch to the lock position.

Does the test lamp illuminate?

--

Go to Step 13

Go to Step 8

7

  1. Using adapter kit J 35616 , connect a test lamp between the fused power door unlock feed and ground at C499.
  2. Press the door lock switch to the unlock position.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 11

8

  1. Using adapter kit J 35616 , connect a test lamp between the fused power door lock feed and ground at C499.
  2. Press the lock switch to the lock position.

Does the test lamp illuminate?

--

Go to Step 10

Go to Step 12

9

  1. Test for continuity of the fused power door lock feed between the door lock actuator and C499.
  2. Repair open in the fused power door unlock feed.

Did you complete the repair?

--

Go to Step 14

--

10

  1. Test for continuity of the fused power door lock feed between the door lock actuator and C499.
  2. Repair open in the fused power door lock feed.

Did you compete the repair?

--

Go to Step 14

--

11

Repair open in the fused power door unlock feed between C499 and the IP wiring harness junction block.

Did you complete the repair?

--

Go to Step 14

--

12

Repair open in the fused power door lock feed between C499 and the IP wiring harness junction block.

Did you complete the repair

--

Go to Step 14

--

13

Replace the lock actuator.

Is the repair complete?

--

Go to Step 14

--

14

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3

Power Door Locks Inoperative - One Motor Cargo

Step

Action

Value(s)

Yes

No

1

Did you review the Door Lock System operation and perform the necessary inspections?

--

Go to Step 2

Go to Power Door Locks Operation

2

Verify the fault is present.

Does the system operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Turn the ignition to the ON position.
  2. Roll down the windows.
  3. Close all of the doors.
  4. Connect a scan tool.
  5. Using the scan tool, check for any DTCs in the body control module (BCM).

Does the scan tool show any DTCs?

--

Go to Diagnostic System Check - Body Control System

Go to Step 4

4

Check that the right rear door lock operates correctly.

Does the right rear door lock operate correctly?

--

Go to Step 5

Go to Power Door Locks Inoperative - One Motor

5

  1. Disconnect the connector to the cargo door lock actuator.
  2. Using adapter kit J 35616 , connect a test lamp between the power door unlock feed from the harness side connector and ground.
  3. Press the lock switch to the unlock position.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 7

6

  1. Using adapter kit J 35616 , connect a test lamp between the power door lock feed from the harness side connector and ground.
  2. Press the lock switch to the lock position.

Does the test lamp illuminate?

--

Go to Step 13

Go to Step 8

7

  1. Using adapter kit J 35616 , connect a test lamp between the fused power door unlock feed and ground at the door contact plate.
  2. Press the door lock switch to the unlock position.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 11

8

  1. Using adapter kit J 35616 , connect a test lamp between the fused power door lock feed and ground at the door contact plate.
  2. Press the lock switch to the lock position.

Does the test lamp illuminate?

--

Go to Step 10

Go to Step 12

13

Replace the lock actuator.

Did you complete the repair?

--

Go to Step 14

--

9

  1. Test for continuity of the fused power door lock feed between the door lock actuator and the door contact plate.
  2. Repair open in the fused power door unlock feed.

Did you complete the repair?

--

Go to Step 14

--

10

  1. Test for continuity of the fused power door lock feed between the door lock actuator and the door contact plate.
  2. Repair open in the fused power door lock feed.

Did you compete the repair?

--

Go to Step 14

--

11

Repair open in the fused power door unlock feed between the door contact plate and the IP wiring harness junction block.

Did you complete the repair?

--

Go to Step 14

--

12

Repair open in the fused power door lock feed between the door contact plate and the IP wiring harness junction block.

Did you complete the repair

--

Go to Step 14

--

14

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3

Power Door Locks Inoperative - One Motor All Except Liftgate/Cargo

Step

Action

Value(s)

Yes

No

1

Did you review the Door Lock System operation and perform the necessary inspections?

--

Go to Step 2

Go to Power Door Locks Operation

2

Verify the fault is present.

Does the system operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Turn the ignition OFF.
  2. Roll down the windows.
  3. Close all of the doors.
  4. Connect a scan tool.
  5. Turn the ignition to the ON position.
  6. Using the scan tool, inspect for any DTCs in the body control module (BCM).

Does the scan tool show any DTCs?

--

Go to Diagnostic System Check - Body Control System in Body Controls

Go to Step 4

4

Remove and inspect the LOCK and the UNLOCK fuses.

Is 1 or both fuses open?

--

Go to Step 7

Go to Step 5

5

  1. Re-install the fuses.
  2. Disconnect the inoperative actuator.
  3. Connect a test lamp from the power door unlock feed on the harness to ground.
  4. Depress the switch to the unlock position.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 6

6

Is this vehicle equipped with 1 lock relay and 2 unlock relays?

--

Go to Step 11

Go to Step 9

7

  1. Repair the open in the fused power door unlock feed or the fused power door lock feed. Refer to Testing for Short to Ground and Wiring Repairs .
  2. Replace the fuse(s).

Did you complete the repair?

--

Go to Step 13

--

8

  1. Connect a test lamp from the power door lock feed on the harness to ground.
  2. Depress the switch to the lock position.

Does the test lamp illuminate?

--

Go to Step 12

Go to Step 10

9

  1. Repair the open in the drivers door power unlock feed or the fused power door unlock feed between actuator and relay. Refer to Wiring Repairs in Wiring Systems.
  2. If no open is found, replace the unlock relay.

Did you complete the repair?

--

Go to Step 13

--

10

  1. Repair the open in the power door lock motor feed between the actuator and the relay. Refer to Wiring Repairs in Wiring Systems.
  2. If no open is found, replace the lock relay.

Did you complete the repair?

--

Go to Step 13

--

11

  1. Repair the open in the drivers door power lock feed or the fused power door unlock feed between the actuator and the relay. Refer to Wiring Repairs in Wiring Systems.
  2. If no open is found, replace the unlock relay or the driver door unlock relay for the left door.

Did you complete the repair?

--

Go to Step 13

--

12

Replace the inoperative actuator.

Did you complete the repair?

--

Go to Step 13

--

13

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3