These tend to go a bit dodgy after a while especially the 5+ year mark. First the door snib becomes really slow to lock/unlock, makes noises, or may not operate at all in either direction.
New actuator is around $200.00+ from dealer it is combined with the doorlock mechanism. It is a sealed, non serviceable assembly.
After reading of someone on LGT opening up his to find the electric motor brushes contaminated with excess grease, I had a go at mine today. What the hell I have nothing to lose but $200.00+ which I would otherwise need to spend anyway .
1. Remove door inner panel (numerous DIY all over the net, look it up if you don't know how.
2. Door lock assembly is held on by 3 bolts where the catch is. Undo them and also the locking cable which goes to external door handle.
3. Prise back the big plastic casing, there are 3 anchors you need to unpick, it then just comes off.
4. Undo this one screw then the whole motor casing comes off; manouvre it out carefully.
5. Case is in two halves, separate carefully using a craft knife or similar blade, it comes apart quite easily with moderate pressure.
6. Motor comes out, probably all oily as hell like mine was.
7. Unpick the two metal tabs then open the motor housing. Careful separating this as the magnetic brush parts are fragile. See all the black gunk which is not meant to be there.
8. Clean the shaft around the coils, then with the brush part (white end cap with contacts inside). I sprayed the white end cap part with engine degreaser, gave it a good rinse with water then used hairdryer. It is too fragile to clean by other means.
9. Carefully put motor back together, again paying close care to the brush contacts which must slip over the coils shaft. I used some long
kebab skewers to get them back on whilst closing up the motor. The tabs can be bent back with a mallet and punch or screwdriver.
10. Clean excess grease out of the motor casing, Mine had heaps, especially around where the worm gear was located. Reinstall motor to casing, then connect it up in the car to ensure you did it properly.
11. Clean two mating surfaces of plastic casing carefully then superglue back together. I used vice clamps to hold it tight whilst it cured.
UPDATE: Superglue came apart, so I have used 2 part epoxy glue this time instead.
12. Reassemble in reverse order, refit into car. Test before refitting door inner panel.
Took me about an hour, now the lock functions as like new