Description
Electric central locking lock for the left front door for Citroën C4 and DS4 vehicles. Driver’s door.
Product Overview
This electric central locking lock is designed for the left front (driver’s) door on Citroën C4 II and DS4 models. It restores reliable central locking operation when the original door lock mechanism becomes faulty. Frequently searched under part numbers 9685351380 and 9135HQ, this unit is suitable for professional garages and DIY mechanics who perform door repairs and central locking diagnostics.
Function and Symptoms
The lock assembly houses the actuator motor and mechanical linkages that convert electrical signals from the central locking system into the physical motion that locks and unlocks the door. Typical failure symptoms include:
- No response from the left front door to central locking commands.
- Intermittent locking/unlocking or delayed operation.
- Grinding or clicking noises inside the door when operating locks.
- Manual lock still works but electrical locking fails.
Replacement Procedure
Basic steps to replace the left front door lock assembly (general guidance):
- Disconnect the vehicle battery before starting to prevent short circuits and protect electronics.
- Remove the door trim panel and the protective vapor/water barrier to access the lock mechanism.
- Disconnect the electrical connector from the lock actuator and detach any locking rods or clips linked to the handle and latch.
- Unscrew and remove the lock unit from the door shell, then fit the new unit in the reverse order.
- Before refitting the trim, test the central locking operation to ensure correct installation and rod linkage alignment.
Installation Recommendations
- Follow manufacturer procedures and keep fasteners and clips in their correct positions to avoid rattles or misalignment.
- Check and, if necessary, clean and protect the electrical connector contacts to prevent future corrosion-related faults.
- Replace any brittle or damaged linkage clips and ensure door moisture seals are intact to reduce water ingress to the mechanism.
- If unsure about the repair, have the installation performed by an experienced technician to guarantee correct adjustment of linkages and calibration of the locking system.
Why The Part Most Commonly Fails
Door lock actuators fail mainly due to mechanical wear and environmental exposure. Common causes include worn or broken plastic gears inside the actuator, motor burnout from extended use, corrosion of electrical connectors, and water ingress from damaged door seals. Frequent short trips, heavy use of central locking, or exposure to moisture accelerate wear and lead to intermittent or complete failure.
Technical Information
- Manufacturer: Stellantis / Citroën
- Model: Citroën C4 II, DS4 (Left Front Door, Driver’s Door, 5-door variants)
- Product Codes: 9685351380, 9135HQ
- Other Numbers: 9135HQ, 9685351380
Notes For Mechanics and DIYers
Search for the unit using the OE part numbers to find matching replacements quickly. Verify door type (left front / driver side) and body version (5-door) before ordering. After installation, confirm smooth operation of both remote and manual locking functions, and recheck linkage alignment to avoid door not latching properly.
Replace the lock assembly to restore dependable central locking and eliminate the inconvenience and security risk of a faulty driver door lock.
