Hi folks,

I have a problem with the door latch on a 1997 XK8 (driver's door). The failure mode is as follows and may ring a bell with you:

- auto door lock (transmission put into Drive) does not always function on driver's door (is okay on passenger door) ie. the inner door handle does not move to locked position.
- central locking does not cause driver's door to lock all the time; can hear the mechanism 'attempt' mechanically but then the alarm chirps continuously. Inner door handle not in locked position
- door will always lock when the physical key is used
- window always auto-lowers but forgets its setting and fails to auto-raise (resetting this works for a while until door latch next fails)
- courtesy lights work as expected, as does 'door-ajar' warning on dash. No problems there.

The car's battery is good and the car is otherwise healthy. Does this sound like a problem with the door latch mechanism (#1 in the diagram) ? Or with the control module (#5 in the diagram), which I think it also in the door ?

I have been told that there's a 'relay' in the door and that this can give trouble, but I don't know what that relay is - probably the control module ?

BTW I see the other current thread here on latch removal, but didn't want to hijack it.

Thanks in advance !
Frank

 

I'll defer to the door latch experts..

 

I have not had my hands on the door mechanism but if it were me I would be looking to see if the micro switch is functional and adjusted properly. I would also check the contacts in the plugs and make sure that they are clean. As for the mechanism I would check that it functions freely and without resistance and that includes the attached linkage. Spraying it with WD40 will clean it up but the lubrication is short term. I would also be looking for the grounding point for that door and make sure it is clean.
The door locking and the window lowering when the key is used tells me that the micro switch is ok.

What I am hearing is that the mechanism is not working when the remote is used leading me to think the security system is not controlling the door latch properly. My thought is that it has a bad connection or a segment that is dirty or in a bind preventing it from completing the process. Like a solenoid not completing the process.

I hope this helps!

 

My security control module went bad and it led to the locks cycling a few times and no doors would lock or unlock with wireless. To me, the fact that you can hear it attempt to move makes it sound more mechanical. I seem to remember years ago on a different forum someone had a similar problem and they removed the latch mechanism and found a broken piece of plastic or broken plastic gear, and rigged something up to fix it themselves. Also, like Gus said, I'd check/adjust the micro switch. I wish I could be of more help, but that's all I remember.

 

When the door latch is trying to lock, is the door handle inside the car moving completely to the locked position?

I would check all the things Gus already suggested. I've never had one completely apart but looking at it there is a plunger type solonoid inside the latch assembly which controls the electronic locking and unlocking and moves the cable attached to the inside door handle. I've seen these go bad on other cars. As they get older, the solonoids weaken. The power locks will still make noise and even move the lock rod but they don't have enough strength to actually lock the door. If anything is corroded or binding inside the door latch or locking mechanism it will make the problem worse.

 

Thanks for the ideas, lads.

When the door latch is trying to lock, the internal handle doesn't move. I can hear the motor 'try' but the handle is in the unlocked position.

It does sound more and more like the solenoid is failing as the electronic logic is obviously still there.

Think I'll just get a new latch, replace it and then repair the old one. After checking the obvious of course, like the actuating rods still being in place