GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Door Lock/Indicator Schematics

Connector End View Reference: Vehicle Access Connector End Views

DEFINITION: This diagnostic table should be used to diagnose a failure of the rear door lock switch or one rear door lock actuator.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Activate the rear door lock switch to the lock and unlock positions.

Do both rear passenger doors lock and unlock?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Install a scan tool.
  2. Monitor the rear door lock switch data parameter in the BCM Data List.

Is the data parameter active without a switch activation?

Go to Step 5

Go to Step 4

4

  1. With the scan tool, monitor the rear door lock switch data parameter in the body control module (BCM) Data List.
  2. Activate the door lock switch to both the lock and unlock positions.

Does the data parameter change with each switch activation?

Go to Step 7

Go to Step 6

5

Disconnect the rear door lock switch.

Does the data parameter now display an inactive state?

Go to Step 10

Go to Step 9

6

  1. Disconnect the rear door lock switch.
  2. Connect a test lamp to ground.
  3. Probe the rear door lock switch ground circuit.

Does the test lamp illuminate?

Go to Step 9

Go to Step 13

7

  1. Disconnect the inoperative door 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 8

Go to Step 14

8

  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 12

Go to Step 15

9

Test for an open or short to ground in the door lock switch lock and unlock signal circuits. Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

Go to Step 19

Go to Step 11

10

Inspect for poor connections at the harness connector of the rear door lock switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 19

Go to Step 16

11

Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 19

Go to Step 17

12

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.

Did you find and correct the condition?

Go to Step 19

Go to Step 18

13

Repair the open in the rear door lock switch ground circuit. Refer to Wiring Repairs.

Did you complete the repair?

Go to Step 19

--

14

Repair the open the door lock actuator lock circuit. Refer to Wiring Repairs.

Did you find and correct the condition?

Go to Step 19

--

15

Repair the open in the door lock actuator unlock circuit. Refer to Wiring Repairs.

Did you find and correct the condition?

Go to Step 19

--

16

Replace the rear door lock switch.

Did you complete the repair?

Go to Step 19

--

17

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the repair?

Go to Step 19

--

18

Replace the rear door lock actuator. Refer to Rear Side Door Latch Replacement.

Did you complete the repair?

Go to Step 19

--

19

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2