Door Lock/Unlock Actuator Circults

Reversible actuators control the power door locks. The power door electrical system controls the actuators by applying battery voltage to one terminal and ground to the other terminal. The Body Control Module (MALL) supplies this battery voltage and ground when the module receives a door lock or unlock input signal. Normally MALL module connector C1 terminals A and C are both at ground. To lock the doors, the MALL module control at connector C1 terminal C switches to battery voltage. The module provides battery voltage to all actuators on CKT 295 (GRY). The opposite side of each actuator is connected to MALL module connector C1 terminal A, which is still at ground. This grounded circuit path is CKT 694 (TAN) for the LH front door lock actuator. The grounded circuit path is CKT 694 (TAN), the normally-closed contacts of the LH front door lock isolation relay and CKT 294 (TAN) for the other three door lock actuators. The actuator in each door runs to move the door locks to the LOCK position. To unlock the doors, the MALL module accomplishes the unlock function in the same way, but the RFA-controlled LH Front Door Lock Isolation Relay in this circuit allows for two methods of unlocking:
^ Only the LH front door locks.
^ All doors unlock.

Pressing the UNLOCK button on the keyless entry transmitter provides an unlock signal to both the RFA and MALL modules. The RFA module turns on its output at terminal E6, which grounds CKT 1391 (LT GRN). The coil of the LH Front Door Lock Isolation Relay energizes, opening the normally-closed relay contacts. This action disables the door lock circuit to the RH front door lock and the rear door locks. At the same time, the MALL module provides battery voltage on CKT 694 (TAN) to the LH front door lock actuator while holding CKT 295 (GRY) at ground. The LH front door unlocks.

When the UNLOCK button is pressed a second time (within 5 seconds of the first press), the RFA module turns off its output at terminal E6, removing the ground from CKT 1391 (LT ORN), de-energizing the isolation relay. The relay contacts close, connecting CKT 694 (TAN) to CKT 294 (TAN). This action provides battery voltage to the rest of the door lock actuators on CKT 294 (TAN) while CKT 295 (GRY) is still held at ground. The rest of the doors unlock.

The door lock actuators are usually powered for just a moment. If they are remain on, an electronic circuit breaker in each actuator opens to protect against damage. Each circuit breaker has a positive temperature coefficient device which resets automatically when voltage is removed from the actuator.