Power Locks: Description and Operation

INTRODUCTION
Power door locks are optional factory-installed equipment on these models. The Remote Keyless Entry (RKE) system is an additional option available on vehicles equipped with the power lock option. On vehicles equipped with the power lock option, all of the doors can be locked and unlocked electrically by operating the switch on either front door panel. On vehicles with the RKE option, the power locks can also be operated by depressing the Lock or Unlock buttons of the RKE radio transmitter.

The RKE system includes an illuminated entry feature, which turns on the courtesy lamps for a timed interval (about thirty-five seconds), when the power locks are unlocked using the RKE transmitter. The RKE system also includes a lock inhibit feature, which automatically unlocks the doors if the power locks are inadvertently locked while the driver door is open with the key in the ignition switch or with the headlamp switch in the On position. The power locks and RKE systems operate with battery power supplied independent of the ignition switch.

Following are general descriptions of the major components in the power lock and RKE systems.

SYSTEM OPERATION
Power Lock Switch
The power locks are controlled by a two-way switch mounted in a bezel on the trim panel of each front door. On models without the Remote Keyless Entry (RKE) option, the switch controls both the battery and ground feeds to the power lock motors. The battery and ground feeds are reversed between the Lock and Unlock switch positions.

On models with the RKE option, the power lock switch controls the battery feeds to the lock and unlock terminals of the power lock and remote keyless entry module. The power lock and remote keyless entry module then relays the correct battery and ground feeds to the power lock motors.

The power lock switches cannot be repaired and, if faulty or damaged, the entire switch must be replaced.

Power Lock Motor
In the power lock and Remote Keyless Entry (RKE) systems, the locks are actuated by a reversible motor mounted within each door. On models without the RKE option, the motor direction is controlled by the battery and ground feeds from the power lock switches. On models with the RKE option, the motor direction is controlled by the battery and ground feeds from the power lock and remote keyless entry module.

The power lock motor cannot be repaired and, if faulty or damaged, the entire motor must be replaced.

Remote Keyless Entry Transmitter
The Remote Keyless Entry (RKE) system transmitter is equipped with two buttons, labeled Lock and Unlock. It is also equipped with a key ring and is designed to serve as a key fob. The operating range of the transmitter radio signal is up to 7 meters (23 feet) from the RKE receiver.

Each transmitter has a different vehicle access code, which must be programmed into the memory of the RKE module in the vehicle in order to operate the RKE system. Refer to the service procedure for Remote Keyless Entry Transmitter Programming.

The transmitter operates on two Duracell DL2016 (or equivalent) batteries. Typical battery life is from one to two years. The transmitter cannot be repaired and, if faulty or damaged, it must be replaced.

Power Lock And Remote Keyless Entry Module
On models with the Remote Keyless Entry (RKE) option, a power lock and RKE module is mounted on the defrost duct beneath the instrument panel, behind the heater-A/C control assembly This module contains the RKE receiver and the RKE system program logic. The module also performs as a smart relay for the power door locks and RKE systems, including the lock inhibit and illuminated entry features.

The RKE receiver has a memory function to retain the vehicle access code of at least one, but no more than two transmitters. The receiver is designed to retain the transmitter codes in memory, even if the battery is disconnected.

The power lock and RKE module receives inputs from the ignition switch, the power door lock switches, the driver door jamb switch, the key-in ignition switch, and the headlamp switch. It also receives the radio signal input from the RKE transmitter. In response to those inputs, it is programmed to control outputs to the power lock motors and the courtesy lamp circuits.

The power lock and remote keyless entry module cannot be repaired and, if faulty or damaged, it must be replaced.

CIRCUIT OPERATION
Circuit A7 from fuse 1 in the Power Distribution Center (PDC) powers circuit F35 through fuse 19 in the fuse block. Circuit F35 supplies power to both door lock switches.

The ground path for the system is through the left door lock switch on the Z3 circuit.

With Remote Keyless Entry
Power for the Remote Keyless Entry (RKE) module is supplied from three sources.

Power is supplied to the RKE module on circuit V6. This circuit is protected by a 20 amp fuse located in cavity 8 of the fuse block. Power for the fuse is supplied from the ignition switch on circuit A31. This circuit is HOT in the Accessory and Run position.

Power for the A31 circuit is supplied by circuit A1. This circuit is HOT at all times and is protected by a 40 amp fuse located in the PDC.

Circuit F35 supplies battery voltage to the RKE module. This circuit is HOT at all times and is protected by a 20 amp fuse located in cavity 19 of the fuse block. Power for the fuse is supplied on circuit A7. The A7 circuit is protected by a 50 amp fuse located in the PDC.

The F35 circuit is used to supply power for the contact side of several relays internal to the RKE module.

Power is also supplied by circuit M1. Circuit M1 is connected to circuit M2 through the dome lamp. Circuit M1 is protected by a 15 amp fuse located in cavity 17 in the fuse block.

Unlock (Using RKE Transmitter)
When the operator selects UNLOCK the RKE module supplies voltage to Circuit P34. Circuit P34 connects to the UNLOCK side of the power lock motors. The ground circuit is completed on circuit P33 to the RKE module.

Lock (Using RKE Transmitter)
When the operator selects LOCK the RKE module supplies voltage to Circuit P33. Circuit P33 connects to the UNLOCK side of the power lock motors. The ground circuit is completed on circuit P34 to the RKE module.

Lock Unlock (Using Door Switches)
Operation of the lock and unlock functions is the same as systems without RKE. The only change between the systems is all of the lock and unlock circuits pass through the RKE module. Refer to the standard door lock circuit descriptions.