GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Automatic Door Locks System Inspect performed?

--

Go to Step 2

Go to Power Door Locks System Check

2

Was the Body Control Module (BCM) Diagnostic System Inspect performed?

--

Go to Step 3

Go to Diagnostic System Check - Body Control System

3

  1. Turn the ignition switch to the LOCK position.
  2. Connect a Tech 2 to the data link connector (DLC).
  3. Turn the ignition switch to the RUN position.
  4. Monitor the unlock and lock switch input on the Tech 2.
  5. While observing the Tech 2 press unlock and lock on the drivers side door lock switch.

Upon pressing unlock and lock, does the Tech 2 indicate unlock and lock switch status as active?

--

Go to Step 5

Go to Step 4

4

  1. Turn the ignition switch to the lock position.
  2. Disconnect the drivers side door lock switch.
  3. Connect a test light between B+ and the drivers side door lock switch harness connector terminal F.

Does the test light illuminate?

--

Go to Step 10

Go to Step 8

5

  1. Using the Tech 2, select the output status.
  2. While observing Tech 2, press lock on driver door switch.

Did Tech 2 indicate output status change?

--

Go to Step 6

Go to Step 7

6

Repair a poor connection or open in CKT 295.

Is the repair complete?

--

Go to Step 9

--

7

  1. Inspect for a poor connection at the BCM.
  2. If the connection is OK, replace the BCM. Refer to Body Control Module Replacement in Body Control System.
  3. After BCM replacement, perform the Setup New BCM Procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Is the repair complete?

--

Go to Step 9

--

8

Repair a poor connection or open in CKT 750.

Is the repair complete?

--

Go to Step 9

--

9

  1. Turn the ignition switch to the LOCK position.
  2. Reconnect the connectors.
  3. Reinstall the components.

Have all the repairs been made?

--

Go to Power Door Locks System Check

--

10

  1. Turn the ignition switch to the LOCK position.
  2. Reconnect the door lock switch.
  3. Disconnect the body control module (BCM) connector C1.
  4. Connect a digital multimeter (DMM).
  5. Measure the voltage between the BCM harness connector C1 terminal B6 and B+.

Is the voltage within the specified range?

9-14 V

Go to Step 11

Go to Step 12

11

Repair a short to ground in CKT 780.

Is the repair complete?

--

Go to Step 9

--

12

  1. Disconnect the drivers side door lock switch.
  2. Connect a DMM.
  3. Inspect continuity between the BCM harness connector C1 terminal B6 and the door lock switch harness connector terminal C.

Is there continuity?

--

Go to Step 14

Go to Step 13

13

Repair a poor connection or open in CKT 780.

Is the repair complete?

--

Go to Step 9

--

14

  1. Connect a digital multimeter (DMM).
  2. Measure the voltage between the BCM harness connector C1 terminal A6 and B+.

Is the voltage within the specified range?

9-14 V

Go to Step 15

Go to Step 16

15

Repair a short to ground in CKT 781.

Is the repair complete?

--

Go to Step 9

--

16

  1. Connect a DMM.
  2. Inspect the continuity between the BCM harness connector C1 terminal A6 and the door lock switch harness connector terminal B.

Is there continuity?

--

Go to Step 7

Go to Step 17

17

Repair a poor connection or open in CKT 781.

Is the repair complete?

--

Go to Step 9

--