Volt

Power Door Lock Key Cylinder Switches Malfunction

The driver window switch monitors the voltage level of the key switch unlock signal circuit. When the key is inserted into the driver door key cylinder and turned to the Unlock position, a switch within the driver door latch closes causing the voltage to drop within the key switch unlock signal circuit. The driver window switch will detect the drop in voltage and will send a serial data message to the BCM commanding all the doors to unlock.

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

Scan Tool Reference

Control Module References for scan tool information

Vehicle OFF, insert the key into the drivers door lock cylinder, turn the key Unlock position while observing the scan tool BCM Driver Door Key Unlock Switch parameter, the parameter should change between Inactive and Active.

1. Vehicle OFF, disconnect the harness connector at the A23D door latch assembly-driver.
2. Test for less than 1 Ω between the ground circuit terminal 8 and ground.

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

3. Vehicle in Service Mode, verify the scan tool Driver Door Key Unlock Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 9 for a short to ground. If the circuit tests normal, replace the S79D window switch-driver.

4. Install a 3 A fused jumper wire between the signal circuit terminal 9 and ground, verify the scan tool Driver Door Key Unlock Switch parameter is Active.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the S79D window switch-driver.

5. If all circuits tests normal, test or replace the A23D door latch assembly-driver.

1. Vehicle OFF, disconnect the harness connector at the A23D door latch assembly-driver.
2. Test for infinite resistance between terminal 8 and terminal 9 with the switch in the open position.

⇒	If not the specified value, replace the A23D door latch assembly-driver.

3. Test for less than 2 Ω between terminal 8 and terminal 9 with the switch in the Unlock position.

⇒	If greater than the specified range, replace the A23D door latch assembly-driver.

Perform the Diagnostic Repair Verification after completing the repair.