Passenger Door Unlock Operation

WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.

When any of the door lock switches are placed in the unlock position, voltage is applied to the door unlock control circuit. The door unlock control circuit supplies voltage to the unlock relay winding and the BCM. Since the other side of the unlock relay winding is connected to battery voltage, the relay is energized. This causes the contacts to close and complete the path from the PWR LKS fuse through the battery voltage circuit. Voltage is then applied to the unlock side of the door lock actuators. Since the other side of the passenger(s) door lock actuators are connected to the normally closed contacts of the lock relay to ground, the doors unlock.

The unlock function can also be accomplished by the BCM supplying voltage to the door lock control circuit during a keyless entry unlock transmission.