Why Can't a Single Car Door Lock?

[Brooks]

If a single car door cannot lock, it may be due to poor lubrication of the locking mechanism, and applying lubricant can help. If reopening and relocking the door still doesn't resolve the issue, it's likely that the door lock assembly is faulty. In such cases, the door lock assembly must be replaced. Common faults include: Motor aging, blown fuses in the switch circuit, malfunction of the central locking control unit, or loosening of the main motor linkage rod. Issues like motor aging, blown fuses, and faults in the central locking control unit typically require direct replacement. Other reasons: If the car's remote key cannot lock the door, it is usually due to a problem with the remote key itself.