Description & Operation: Notes

NOTE: This article applies to "new style" "C" & "K" Series vehicles equipped with 4.3L, 4.8L, 5.3L and 6.0L engines. For "old style" "C" & "K" Series vehicles, see POWER DOOR LOCKS -- ESCALADE, PICKUP, TAHOE & YUKON DENALI article.

NOTE: On some vehicles, the power door lock system is integrated with the Remote Keyless Entry (RKE) system. For information on RKE, see appropriate REMOTE KEYLESS ENTRY SYSTEMS article.

Each door is equipped with a reversible door lock actuator that will lock or unlock door depending on polarity of supply voltage. Polarity of supply voltage is determined by the position of door lock switches or a BCM command. There are 2 levels of door lock systems, base and uplevel. Uplevel systems include RKE and automatic door locks. Uplevel systems add a driver door unlock relay to allow independent unlocking of driver door.

On base system, door LOCK switch supplies voltage to door lock relay. Door lock relay then supplies voltage to all door lock actuators. Door lock actuators ground through door unlock relay. Door UNLOCK switch supplies voltage to door unlock relay. Door unlock relay then supplies voltage to all door lock actuators. Door lock actuators ground through door lock relay.

On uplevel systems, door switches operate passenger doors as in base system. Driver door unlock is operated separately through driver door unlock relay controlled by BCM. Door unlock switch sends unlock signal to BCM and BCM sends voltage to driver door unlock relay to unlock driver door. When using RKE or when automatic door lock system, BCM supplies voltage to door lock relay or door unlock relay to activate door locks.