When any of the door lock switches are placed in the lock position, voltage is applied to the door lock relay control circuit and the lock relay winding. Since the other side of the lock relay winding is connected to ground, the relay is energized. This causes the contacts to close and complete the path from the PWR/ACCY fuse through the battery voltage circuit. Voltage is then applied to the door lock actuator lock circuit to the lock side of the door lock actuators. Since the other side of the all the door lock actuators are connected through the door lock actuator unlock circuit to the normally closed contacts of the unlock relay to ground, the doors lock.

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Door Locks Description and Operation

Electrical Information Reference

Ignition ON, command the doors to LOCK and UNLOCK by pressing the upper or lower part of a door lock switch, the doors should LOCK and UNLOCK.

All Door Locks Inoperative

1. Ignition OFF, disconnect the door lock relay.
2. Test for less than 1.0 ohm between the ground circuit terminal D and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal C and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. If all circuits tests normal, test or replace the door lock relay.

Door Lock Switch Inoperative

1. Ignition OFF, disconnect the harness connector at the appropriate door lock switch.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal E and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

3. Ignition OFF, reconnect the door lock switch and disconnect the harness connector at door lock relay.
4. Ignition ON, verify that a test lamp illuminates between the LOCK control circuit terminal F and ground while pressing the door lock switch.

⇒	If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the door lock switch.

5. Verify that a test lamp illuminates between the UNLOCK control circuit terminal A and ground while pressing the door lock switch.

⇒	If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance.

6. If all circuits test normal, test or replace the door lock switch.

Door Latch Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate door latch assembly.
2. Test for less than 5.0 ohms between the control circuit terminal A and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuits test normal, test or replace the door lock relay.

3. Test for less than 5.0 ohms between the control circuit B and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the door lock relay.

4. Connect a test lamp between control circuit terminal A and control circuit terminal B.
5. Ignition ON, command the doors to LOCK and UNLOCK by pressing the door lock switch. The test lamp should illuminate when commanding the LOCK and UNLOCK states.

⇒	If the test lamp remains OFF during either of the commands, test either control circuit for a short to ground or open/high resistance.

⇒	If the test lamp is always ON, test either control circuit for a short to voltage.

6. If all circuits test normal, test or replace the door latch assembly.

Door Lock Switch

1. Ignition OFF, disconnect the harness connector at the appropriate door lock switch.
2. Test for infinite resistance between the signal terminals D and A and the B+ terminal E with the switch in the open position.

⇒	If not the specified value, replace the door lock switch.

3. Test for less than 2 ohms of resistance between the signal terminal A and the B+ terminal E with the switch in the LOCK position.

⇒	If greater than the specified range, replace the door lock switch.

4. Test for less than 2 ohms between the signal terminal D and the B+ terminal E with the switch in the UNLOCK position.

⇒	If greater than the specified range, replace the door lock switch.

Door Latch

1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
2. Install a 20-amp fused jumper wire between the control terminal A and 12 volts. Momentarily install a jumper wire between the control terminal B and ground. The door latch should perform the LOCK/ UNLOCK function.

⇒	If the function does not perform as specified, replace the door latch.

3. Reverse the jumper wires; the door latch should perform the UNLOCK/LOCK function.

⇒	If the function does not perform as specified, replace the door latch.

Relay Test

1. Ignition OFF, disconnect the door lock relay.
2. Test for 60-200 ohms between terminals 85 and 86.

⇒	If not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If less than infinite resistance, replace the relay.

4. Test for less than 2 ohms between terminals 30 and 87A.

⇒	If greater than the specified range, replace the relay.

5. Install a 3-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.

⇒	If greater than the specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.