Symptoms

One door will no longer lock or unlock using the front door knobs or key.

Tools required

• Torx T30 screwdriver or bit with drive
• Phillips screwdriver
• Dry graphite lubricant
• Lineman’s Pliers
• Sidecutter pliers.
• 1 small ‘zap strap’ or ‘cable tie’.

Door lock mechanism failures can be due to a number of problems. I will address removal and repair of a typical problem associated with the electric lock mechanism.
Right rear door is used in this example.

No need for great detail covering removal of the door panel. It is well covered on the ‘net and in the Bentley’s manual.

1. Remove the 3 Philips head screws and the manual door lock knob, pull the panel away from the door by disengaging the clips then pull it straight up.
2. Remove the hook from the door lever and unplug the power window switch. Set panel aside. Gently pull away the inner seal from the adhesive.
3. Remove the black plastic screw pin at the pivot point for the manual lock mechanism using the Phillips driver and pull the pivot and anchor out of the door.
4. Push the clip for the latch release cable forward to release it from the door.
5. Cut the cable tie holding the wire to the door using the Sidecutters.
6. Remove the three T30 screws holding the lock/latch mechanism in place. One is hidden under the weather stripping.
7. Pull the lock/latch mechanism from the door.
8. Unplug the electrical harness by sliding the release over and pulling it off.
9. Remove the plastic weather wrapping.
10. Remove the power lock actuator off of the latch by sliding it slightly forward off of the tabs and pulling it away.
11. Remove the black plastic cover by pulling the wedge tab away from the body.
    
12. The lock mechanism is powered by an electric motor that turns a small gear that in turn spins a larger gear. These two gears can wear slightly and bind. Turn the larger gear and you may feel it ‘unbind’.
    After turning it so that it is no longer jammed spray a reasonable amount of graphite onto all the moving parts but NOT into the motor. Graphite is a conductor and may short the motor.
    
13. Test the motor by plugging it back into the harness connector and locking and unlocking one of the front doors. It should now operate correctly. If not you will need to check electrical power to the actuator (See below) and possibly replace the defective unit.
    
14. Reinstall the lock actuator on the latch mechanism. Make certain the holes line up and press it back into place.
15. Snap the black cover into place.
16. Stick the weather cover back in place.
17. Plug the actuator into the harness.
18. Slide the entire mechanism back into the door (the lock rod and latch cable do not need to be in place) noting the perfect cutout in the metal for this procedure.
19. Install all three T30 screws loosely before tightening.
20. Install the new cable tie to the wires to hold them in place.
21. Install the lock rod into the latch making sure it doesn’t interfere with the wires to the window/switch and then install the pivot. Install the white plastic pivot, slide the anchor into the pivot and door then press the pin into the centre of the anchor.
22. Install the latch cable and slide the retainer clip into place.
    
    You may want to take this opportunity to lubricate the window pinion gear with synthetic grease or dry graphite.
    Install the insulation making certain the lock rod points up through the slit. The insulation simply presses into the adhesive.
    
23. Remove the centre retaining clip, using the Lineman’s pliers, from the door and slide it into the door panel.
24. Reinstall the door panel.
    
    Test power to the lock actuator.
    Using a test light or multimeter check for vehicle voltage between blue and white or blue and black wires when manipulating the front locks.
    
    
    
    Door panel removed.
    Note location of clip for door latch just to the right of the green cable shield and the white pivot for the door lock to the left centre with the lock rods connected to it.
    The inner T30 is hidden by the wire harness to the right.
    
    
    
    Hidden Torx 30 under weather-stripping. Remove all three T30’s and then pull the entire latch/lock mechanism from door. Two here in the doorsill and one inside of the door.
    
    
    
    The complete latch/lock mechanism removed from the door with weather cover in place.
    
    
    
    Weather cover removed. Disconnect the electrical connector by sliding the black lock down until the blue pins are at the top of the grooves then pull straight off.
    
    
    Pull the actuator off of the latch mechanism by pulling the ridged part away and the actuator forward.
    
    
    
    The actuator. Pull the black cover up and off by releasing the tab on the side.
    
    
    
    Actuator with cover removed. Note black graphite lubricant on gear at opening in top and side.
    Test and reinstall.
    
    

Article by Shayne Mcguire