GM 15110508 Front Side Door Lock

The power door lock system operates the door lock actuators in each door, with the system consisting of switches, actuators, Body Control Module (BCM), and associated wiring. Diagnosis typically involves checking the wiring connections and actuators for minor faults that can be easily repaired. The system is operated by bi-directional solenoids located in the doors, with lock switches having two positions: Lock and Unlock. These switches send a signal to the BCM, which then sends a signal to the door lock solenoids. It is important to check the circuit protection first, as some vehicles use a combination of circuit breakers and fuses. If no voltage is present at the switches, the wiring between the fuse panel and switches should be checked for shorts and opens. If voltage is present, the switch should be tested for continuity, and if there is no continuity in both switch positions, it should be replaced and check the wiring between the switch and the door lock solenoid. If all but one lock solenoids operate, the trim panel from the affected door should be removed to check for voltage at the solenoid while the lock switch is operated; if the inoperative solenoid is receiving voltage, it should be replaced and if it isn't, an open or short in the wire between the lock solenoid and the relay should be checked. For the keyless entry remote, the battery should be replaced when the transmitter doesn't operate the locks at a distance of ten feet, with the normal range being about 30 feet. To replace the battery, the case halves should be carefully separated using a small screwdriver, and then the three-volt, lithium battery should be replaced before snapping the case halves together.

To replace the latch, first raise the window completely and remove the door trim panel along with the rear section of the water shield. Detach the latch rods from the lock cylinder, outside handle, and inside handle by working through the opening in the door. Remove the three Torx-head mounting screws, which may require an impact-type screwdriver to loosen, and then take the latch out of the door. If possible, disconnect the rods while the latch is still in the door; if not, pull the latch out with the rods attached, then disconnect the rods and electrical connectors. Installation follows the reverse of removal, ensuring the door latches and unlatches properly. For the lock cylinder, remove the outside door handle, disconnect the link, and use a screwdriver to push the key lock cylinder retainer off before withdrawing the lock cylinder from the door handle. Installation is again the reverse of removal. To replace the outside handle, disconnect the handle link, remove the mounting nut(s), and detach the handle from the door. Position the new handle, attach the link, and securely install the nut(s). For the inside handle, first remove the door trim panel, then carefully disengage the clips to remove the inside handle trim bezel. Disconnect the latch rod from the handle assembly, remove the mounting bolt, and slide the handle forward to detach it from the location holes before taking it out of the door. Minor adjustments for latch alignment can be made by loosening the bolts on the latch striker, which is mounted opposite the latch, allowing for slight movement up/down or in/out. After adjustments, retighten the striker mounting bolts and check for proper latch operation.

A few drops of light oil or lock lubricant should be used for the hinges and latch assemblies.

If only one solenoid is inoperative, remove the trim panel from the affected door and check for voltage at the solenoid while operating the lock switch. If voltage is present, replace the solenoid; if not, check for an open or short in the wire between the lock solenoid and the relay.

The hinges and latch assemblies should be lubricated once every 3000 miles or every three months.