Door Lock Actuator Failure

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Contents

Lock Actuator Failure

Complaint

When operating the car locks - whether unlocking or locking - a malfunction can occur with a lock actuator. When this occurs, it can prevent that particular door from opening. Usually this type of complaint is intermittent. Over time, the frequency of the lock actuator malfunction will increase.


Cause

The lock actuator internal circuitry has a tendency to fail from normal operation. The bracket on the actuator for the interior release cable can break, preventing the door to be opened from the interior. Certain model vehicles are prone to having issues with their lock actuators. The failure of a lock actuator will not always result in a fault being stored. Operation malfunctions will be observed when operating the central locking system. Sporadic lock operation or the inability to open a door when the door is unlocked, are common symptoms of failing or failed locks actuators. The models that typically have lock actuator failures include but aren't limited to: E53, E46, E83 and E90. Some common symptoms of a failed lock actuator would be intermittent or no operation, multiple activations after unlocking request, inability to open a door either from the inside or outside of the vehicle when it appears to be unlocked. At times a physical failure of the actuator can make it impossible for the door to be opened from the inside of the vehicle. This typically occurs with the driver’s door. The lock actuator is broken where the release cable connects to the actuator. With this type of problem, the actuator will require replacement due to physical damage of the actuator housing. To determine whether the fault is electrical or mechanical, a visual inspection of the lock actuator is recommended.

  • The picture displayed is of an actuator from an E53 that is physically broken at the release cable bracket. An actuator with this type of damage will require replacement.
    • For example, an E90 with a central locking malfunction. The locks for the individual doors are inoperative, but the actuators for the trunk latch and the fuel filler door remain operational. This is because they are on a different circuit. Upon further inspection, one of the fuses in the JBE that supplies power to the lock actuators was blown causing all to be inoperative. When a new fuse is installed operation of the locks is restored. After function testing the central locking and monitoring for any abnormal operation, the driver’s door lock actuator was found to be malfunctioning when working the central locking. That component on the circuit is responsible for the burning through the fuse, and causing the central locking malfunction.


Correction

The only fix for a faulty lock actuator is to replace it. The repair procedure for individual lock actuators is different for each model. It is usually required to remove the door panel and vapor barrier for the door that is having the actuator replaced. Certain vehicles require that the window regulator be removed to replace the actuator. A special tool is required on a vehicle with the soft close feature to position the actuator in the proper place for installation.

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