The brief
Mr William's A160 had a door lock playing up, it wouldn't lock from the remote, so the car couldn't be secured properly with the key fob. He was referred to us for it. A door that won't lock is a real security problem, so it wants sorting, and it pays to take it to someone who knows the car rather than guessing. When one door won't lock or unlock with the central locking, the culprit is almost always the lock actuator on that door, the motorised latch assembly that does the locking, unlocking and catching. The little motor wears, the plastic gears strip, and the micro-switches go flaky, so it stops responding reliably. A lock actuator that's started failing only gets worse, so it needs replacing.
The diagnosis
The door card came off and the lock told the story, the actuator's motor and gears worn, not driving the latch cleanly, which is why that door wouldn't lock from the remote. The wiring and the central locking module checked out, it was the lock unit on that door. That's a replacement, you don't rebuild the actuator on the car, so the call was a complete lock unit, coded and tested with the central locking.
The work
The door card was removed, the failed lock actuator unbolted and taken out, and a new genuine Mercedes-spec lock assembly fitted, connected up, and the latch and linkages adjusted so the door catches and releases cleanly. The new unit was registered as needed so the central locking recognised it, and the door card refitted. A check confirmed the door locked and unlocked reliably from the remote and the switch along with the others, the latch catching first time and releasing cleanly.
The outcome
A door that locks and unlocks every time from the remote with the rest of the car, latches first time, and does it quietly. The A160 went home with the lock sorted. A failing door lock leaves the car insecure and only gets worse, so changing the actuator put it right.
