GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open.

1

Was the door locks system check performed?

--

Go to Step 2

Go to Power Door Locks System Check

2

Perform the body control module (BCM) diagnostic system check.

Are any door lock DTCs present?

--

Go to Body Control Module System Check

Go to Step 3

3

  1. Connect the scan tool to the data link connector (DLC).
  2. Monitor the BCM door lock relay output while activating the lock switch to the LOCK position.

Does the output change from OFF to ON?

--

Go to Step 4

Go to Step 10

4

  1. Remove the ignition key from the ignition switch.
  2. Remove the lock relay at the left IP junction block electrical connector.
  3. Connect a test lamp between ground and J 35616 .
  4. Frontprobe the left IP junction block lock relay terminal 85 (CKT 195).
  5. Activate the door lock switch to the LOCK position.

Does the test lamp light?

--

Go to Step 6

Go to Step 5

5

  1. Remove the key from the ignition switch.
  2. Connect a test lamp to ground.
  3. Backprobe the left IP junction block connector C1 terminal F10.
  4. Activate the door lock switch to the LOCK position.

Does the test lamp light?

--

Go to Step 7

Go to Step 8

6

Replace the door lock relay.

Is the repair complete?

--

Go to Power Door Locks System Check

--

7

Replace the left IP junction block.

Is the repair complete?

--

Go to Power Door Locks System Check

--

8

  1. Connect a test lamp to ground.
  2. Backprobe the BCM connector C3 term A8.
  3. Activate the door lock switch to the lock position.

Does the test lamp light?

--

Go to Step 9

Go to Step 11

9

Repair open or short to ground in CKT 195 between the BCM and left IP junction block connector C1.

Is the repair complete?

--

Go to Power Door Locks System Check

--

10

  1. Connect J 39200 to ground.
  2. Backprobe the BCM connector C2 terminal A2.

Is the voltage as specified?

12-14V

Go to Step 12

Go to Step 11

11

Inspect for a poor connection at the BCM connectors. If OK, replace the BCM.

Is the repair complete?

--

Go to Power Door Locks System Check

--

12

  1. Connect J 39200 to ground.
  2. Backprobe the BCM connector C2 terminal A2.
  3. Activate either lock switch to the LOCK switch.

Is the reading less than the specified value?

1V

Go to Power Door Locks System Check

Go to Step 13

13

Replace the lock switch(es) that pulled less than the specified value when activated to the LOCK position.

Is the repair complete?

1V

Go to Power Door Locks System Check

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