GM Service Manual Online
For 1990-2009 cars only

The keyless entry system includes the following components:

    • A hand-held radio transmitter
    • A remote control door lock receiver

When a button is pushed, the transmitter sends a digitally encoded radio signal to the receiver. The range of the transmitter is approximately 7 m (12 ft). The transmitter controls the following functions:

    • The door locks (all doors or just the driver's door)
    • The rear compartment lid release

Door Locks

When the transmitter UNLOCK button is pushed once, the driver's door unlocks. The remote control door lock receiver performs the following functions:

  1. Receives the transmitted signal
  2. Applies battery voltage to CKT 694

This action applies battery voltage directly to the left front door lock motor. The left front door lock motor is grounded through the following components:

    • The left instrument panel wiring harness junction block
    • The door lock relay

When the UNLOCK button is pushed twice within 5 seconds, the remote control door lock receiver applies battery voltage to CKT 694 and CKT 194. The remote control door lock receiver directly drives the driver's door motor. The door unlock relay in the left instrument panel wiring harness junction block energizes, causing the passenger doors to unlock. When the UNLOCK or the TRUNK RELEASE button is pushed, the receiver grounds CKT 395. This action turns on the interior lamps. Refer to Interior Lights Schematics in Lighting Systems.

When the LOCK button is pushed, the remote control door lock receiver applies battery voltage to CKT 195. This action energizes the door lock relay in the left instrument panel wiring harness junction block, which locks all the doors. The left front door lock motor is grounded through the remote control door lock receiver. The other door lock motors are grounded through the door unlock relay. When the LOCK button is pushed within 5 seconds after the initial lock cycle, the horn will chirp in order to confirm the LOCKED state. The remote control door lock receiver activates the horn chirp by grounding CKT 28. Refer to Horn Schematics in Horns.

Security Features

In order to prevent the unwanted possibility of the transmitter signal from being recorded and retransmitted to unlock the doors, a rolling code is incorporated into the remote control door lock receiver. When the transmitter is used, the remote control door lock receiver increments the rolling code to the next code. If the transmitter is activated outside the range of the remote control door lock receiver for more than a predetermined number of actuations, the transmitter will no longer be synchronized with the remote control door lock receiver's rolling code. The transmitter will not be functional until the transmitter is resynchronized with the remote control door lock receiver. In order to resynchronize the transmitter to the remote control door lock receiver, perform the following procedure:

  1. Stand within the signal reception range of the remote control door lock receiver.
  2. Hold both the LOCK and the UNLOCK buttons for approximately 10 seconds.
  3. Ensure that the system produces a cycling of the locks. This action ensures that the system is now synchronized and operational.

Rear Compartment Lid Release

The rear compartment lid release is operated by applying battery voltage to the rear compartment lid release motor when the TRUNK RELEASE button on the transmitter is pushed. CKT 1737 must be grounded in order for the remote control door lock receiver to activate the rear compartment lid release motor. CKT 1737 is grounded when the gear selector is in one of the following positions:

    • PARK
    • NEUTRAL