Driver and Passenger Door Lock Operation (without Keyless Entry)
WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. 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 lock position, voltage is applied to the door lock 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 motor 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 motor unlock circuit to the normally closed contacts of the unlock relay to ground, the doors lock.