GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you perform A Diagnostic System Check for the Doors system?

Go to Step 2

Go to Diagnostic System Check - Power Door Systems

2

Verify that the power door locks are inoperative.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Connect a scan tool.
  2. Using the scan tool, observe the door lock switch inputs into the BCM.

Are any of the door lock switch inputs into the BCM active.

Go to Step 4

Go to Step 5

4

Test the appropriate door lock switch input circuit into the BCM for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 26

5

With the scan tool, observe the door lock switch inputs while pressing lock and unlock on both the left and right door lock switches.

Does the scan tool display Lock for the lock conditions and Unlock for the unlock conditions from both switches?

Go to Step 6

Go to Step 7

6

  1. Put all the door locks in the unlock position by hand.
  2. Command the door locks to lock from a door lock switch.
  3. Put all the door locks in the lock position by hand.
  4. Command the door locks to unlock from a door lock switch.

Do any of the door locks, except the driver's door lock, lock or unlock?

Go to Step 17

Go to Step 9

7

Test the ground circuit to each door lock switch for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 8

8

Test the appropriate door lock switch input circuit to the BCM for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 22

9

Test the door lock relay battery positive feed circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 10

10

Test the door lock relay battery positive feed circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 11

11

Test the door lock relay and the door unlock relay ground circuits for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 12

12

Test the door lock relay control circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 13

13

Test the door lock relay controlled circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 14

14

Probe the controlled circuit of each relay output to the door lock actuators at the relay, except the driver's door unlock relay controlled circuit, with a test lamp connected to a good ground, while commanding the door locks to lock and unlock from a door lock switch.

Did the test lamp illuminate for each circuit when commanded to lock or unlock?

Go to Step 15

Go to Step 21

15

Did the test lamp stay illuminated for any of the controlled outputs even when the scan tool was not commanding the door locks to do anything?

Go to Step 25

Go to Step 16

16

Test the door lock relay and the door unlock relay controlled circuits for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 20

17

  1. Remove the door lock relay and the door unlock relay.
  2. Probe the control circuit of each relay, except the driver's door unlock relay control circuit, with a test lamp connected to battery positive voltage, while commanding the door locks to lock and unlock with the scan tool.

Did the test lamp illuminate for each circuit when commanded to lock or unlock?

Go to Step 14

Go to Step 18

18

Test the appropriate relay control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 19

19

Inspect for poor connections at the BCM. 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 27

Go to Step 23

20

Inspect for poor connections at 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 27

Go to Step 24

21

Inspect for poor connections at the door lock relays. 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 27

Go to Step 25

22

Inspect for poor connections at the door lock switch. 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 27

Go to Step 26

23

  1. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.
  2. Perform a Set Up New BCM procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Did you complete the repair?

Go to Step 27

--

24

Replace the defective door lock actuator(s). Refer to Door Lock Actuator Replacement .

Did you complete the repair?

Go to Step 27

--

25

Replace the defective door lock or unlock relay.

Did you complete the repair?

Go to Step 27

--

26

Replace the defective door lock switch. Refer to Door Lock Switch Replacement .

Did you complete the repair?

Go to Step 27

--

27

  1. Replace the DOOR LOCK Fuse if neccessary.
  2. Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 3