GM Service Manual Online
For 1990-2009 cars only

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Action

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Schematic Reference: Door Lock/Indicator Schematics

DEFINITION: This diagnostic should be used to diagnose a failure of the driver door lock actuator (lock, unlock or both).

1

Did you perform the Power Door System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Door Systems

2

Actuate all the door lock switches to both the lock and unlock positions.

Did the driver door lock and unlock from all of the switches?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Did the passenger door(s) lock and unlock from all of the switches?

Go to Step 4

Go to Power Door Locks Inoperative - All Doors and Switches

4

Did the drivers door lock?

Go to Step 6

Go to Step 5

5

Did the driver door unlock?

Go to Step 8

Go to Step 11

6

  1. Remove the driver door unlock relay from the body relay block.
  2. Connect a test lamp between B+ and the driver door unlock relay control circuit at the body relay block.
  3. Install a scan tool.
  4. Command the doors to unlock.

Did the test lamp illuminate?

Go to Step 7

Go to Step 13

7

  1. Monitor the passenger door unlock input data value on the scan tool.
  2. Actuate a door lock switch to the unlock position.

Did the data value change from inactive to active when the switch was actuated?

Go to Step 9

Go to Step 16

8

  1. Remove the driver door unlock relay.
  2. Connect a test lamp between the driver door unlock relay ground circuit at the body relay block and B+.

Did the test lamp illuminate?

Go to Step 14

Go to Step 21

9

Connect a test lamp between the battery positive voltage circuit on the coil side of the driver door lock relay at the fuse block and a good ground.

Did the test lamp illuminate?

Go to Step 10

Go to Step 22

10

Connect a test lamp between the battery positive voltage circuit on the switched side of the driver door lock relay at the body relay block and a good ground.

Did the test lamp illuminate?

Go to Step 14

Go to Step 22

11

  1. Disconnect the driver door lock actuator.
  2. Connect a test lamp between the door lock actuator lock circuit at the door lock actuator harness connector and a good ground.
  3. Actuate a door lock switch to the lock position.

Did the test lamp illuminate?

Go to Step 12

Go to Step 19

12

  1. Connect a test lamp between the door lock actuator unlock circuit at the door lock actuator harness connector and a good ground.
  2. Actuate a door lock switch to the unlock position.

Did the test lamp illuminate?

Go to Step 16

Go to Step 20

13

Test for an open in the driver door unlock relay control circuit between the BCM and the driver door unlock relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 25

Go to Step 17

14

Inspect for poor connections at the driver door unlock relay. 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 25

Go to Step 18

15

Check for an open in the door unlock control circuit between the BCM and the door lock switches. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 25

Go to Step 17

16

Inspect for poor connections at the driver 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 25

Go to Step 23

17

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 25

Go to Step 24

18

Replace the driver door unlock relay.

Did you complete the repair?

Go to Step 25

--

19

Repair the open in the door lock control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 25

--

20

Repair the open in the door unlock control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 25

--

21

Repair the open in the driver door lock relay ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 25

--

22

Repair the open in the driver door lock relay battery positive voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 25

--

23

Replace the door lock actuator. Refer to Front Side Door Lock Actuator Replacement .

Did you complete the repair?

Go to Step 25

--

24

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the repair?

Go to Step 25

--

25

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2