For 1990-2009 cars

Battery voltage is applied at all times through the door lock fuse to the power door lock control module. The power door lock control module is permanently grounded at G203.

When either of the front power door lock switches is pressed to the UNLOCK position, the power door lock control module receives a ground signal at the UNLOCK INPUT terminal. When the ground signal is received, the power door lock control module applies a voltage to the UNLOCK OUTPUT terminal and applies a ground to the LOCK OUTPUT terminal.

With both power and ground applied to the power door lock motors (in the power door lock actuators), the power door lock motors turn. This moves the push/pull mechanical linkages in the doors which unlocks the doors.

When either of the front power door lock switches is pressed to the LOCK position, the power door lock control module receives a ground signal at the LOCK INPUT terminal. When the ground signal is received, the power door lock control module applies a voltage to the LOCK OUTPUT terminal and a ground to the UNLOCK OUTPUT terminal.

With both power and ground applied to the power door lock motors (in the power door lock actuators), the power door lock motors turn. This moves the push/pull mechanical linkages in the doors which unlocks the doors.