GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 1999 🢒 S/T Isuzu - 2WD 🢒 Body and Accessories 🢒 Doors 🢒 Power Door Locks Inoperative - All Doors and Switches

Step

Action

Value(s)

Yes

No

1

Did you perform the power door locks diagnostic system check?

--

Go to Step 2

Go to Power Door Locks System Check

2
  1. Install the scan tool.
  2. Turn the engine OFF.
  3. Trun the ignition to the RUN position.

Are there any codes in the BCM?

--

Go to Section 8D

Go to Step 3

3

Inspect the MIR/LKS fuse 7 at the IP fuse block.

Is the fuse open?

--

Go to Step 4

Go to Step 16

4
  1. Connect a test lamp between the MIR/LKS fuse terminal A and terminal B in the IP fuse block.
  2. Leave the test lamp connected.

Does the test lamp light?

--

Go to Step 5

Go to Step 7

5

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative terminal of the battery.
  2. Remove the body relay block connector.
  3. Reconnect the negative battery terminal.

Does the test lamp light?

--

Go to Step 6

Go to Step 25

6
  1. Repair a short to ground in CKT 840 between fuse 7 and the body relay block.
  2. Reinstall the connector to the body relay block.

Is the repair complete?

--

Go to Power Door Locks System Check

--

7

Press the driver door lock button.

Does the test lamp light immediately?

--

Go to Step 8

Go to Step 9

8

Repair the short to ground in CKT 195.

Is the repair complete?

--

Go to Power Door Locks System Check

--

9

Press the driver door unlock button.

Does the test lamp light immediately?

--

Go to Step 10

Go to Step 11

10

Repair the short to ground in CKT 194.

Is the repair complete?

--

Go to Power Door Locks System Check

--

11

Press the passenger door lock button.

Does the test lamp light immediately?

--

Go to Step 12

Go to Step 13

12

Repair a short to ground in CKT 195.

Is the repair complete?

--

Go to Power Door Locks System Check

--

13

Press the passenger door unlock button.

Does the test lamp light immediately?

--

Go to Step 14

Go to Step 15

14

Repair a short to ground in CKT 194.

Is the repair complete?

--

Go to Power Door Locks System Check

--

15
  1. Replace the MIR/LKS fuse.
  2. Inspect the system.

Is the system operating correctly?

--

Go to Power Door Locks System Check

--

16
  1. Use a scan tool in order to monitor the state of the door unlock relay feedback CKT 194.
  2. Press the driver door unlock switch.

Does the door unlock relay feedback signal change to ON?

--

Go to Step 17

Go to Step 18

17

Inspect the PWR LKS fuse 14 for an open.

Is the fuse open?

--

Go to Step 19

Go to Step 23

18

Repair an open in CKT 194.

Is the repair complete?

--

Go to Power Door Locks System Check

--

19
  1. Connect a test lamp between the IP fuse block PWR LKS fuse 14 terminal A and terminal B.
  2. Leave the test lamp connected.

Does the test lamp light?

--

Go to Step 20

Go to Step 22

20
  1. Remove the following relays:
    2. • The left door unlock relay
    • The door lock relay
    • The door unlock relay
  2. Observe the test lamp in order to note if the lamp goes out when each relay was removed.
  3. Replace the relay as needed.

Does the test lamp remain lighted?

--

Go to Step 24

Go to Step 22

21

Repair the short to ground in CKT 1740.

Is the repair complete?

--

Go to Power Door Locks System Check

--

22
  1. Replace the PWR LKS fuse 14.
  2. Inspect the system.

Is the system operating correctly?

--

Go to Power Door Locks System Check

--

23

Repair an open in CKT 1740.

Is the repair complete?

--

Go to Power Door Locks System Check

--

24

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative terminal of the battery.
  2. Disconnect the body relay block connector.
  3. Reconnect the negative battery terminal.

Does the test lamp light?

--

Go to Step 21

Go to Step 25

25

Replace the body relay block.

Is the replacement complete?

--

Go to Power Door Locks System Check

--