Driver & Passenger Door Unlock Operation - w/o Keyless Entry
WARNING: This page is about a different car, the 2002 GMC Safari and 2002 Chevrolet Astro. 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 and the unlock relay winding. Since the other side of the unlock relay winding is connected to ground, the relay is energized. This causes the contacts to close and complete the path from the PWR ACCY circuit breaker through the battery voltage circuit. Voltage is then applied to the unlock side of the door lock actuators. Since the other side of the door lock actuators are connected to the normally closed contacts of the lock relay to ground, the doors unlock.