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Every so often when I unlock the doors either with remote fob or the key from outside or the handle from inside the door locks go through a cycle of several open and locks before stopping in the open position. They lock normally 1 or 2 stage with the remote and will unlock normally if I immediately open after locking but if I leave it a while then the cycling starts again.
Battery is about 2 years old and fully charged (always connected to a charger/tender if not used for more than a few days).
I just got back from a 40 mile fault-free run (no issues detected on my Ultragauge) and it happened again when I opened the drivers door from the inside. The Ultragauge showed alternator output of around 14v during the trip so difficult to think it's a battery issue.
The only other electrical "issue" is that if the car has not been used for say 3 weeks (on a battery tender) I have to use the key to unlock as the remote fob doesn't work and then the alarm goes off until I press the unlock button on the remote fob but I've always put this down to the car being in low-power shutdown mode.
It's not a major deal just a bit irritating. Any suggestions as to the cause much appreciated.
A failing door latch microswitch is the first thing that comes to mind.
Graham
Thank you Graham. Are they easy to get at to check?
Just been back up to the car and all working perfectly after a couple of hours so whatever it is it's not completely failed yet .
Well, taking the latch out is easier with the window up and small hands. Take the battery off as you don’t want to loose fingers if the window comes down. Safety first. You sound handy with a wrench though. So, with Rev Sam’s video, note there’s a minor error in the vertical link he broke. The plastic sleeve just slides off the link and you can seperate the two parts of the joint. So get to it.
If you’re changing the latch’s microswitches, do all of them. Problem is how to attach the replacements in the unit - rivets? Forum members have mentioned ingenious methods using glued ear bud stems etc.
Steve, FWIW that's always a clear sign to charge the battery on my 98.
John
Hi John.
Interesting that you seem to have had the same problem. Like many on here my first goto culprit is the battery but in this case I'm confident it's good. Always on charge when car not used and problem happened today at end of long run when I know the alternator was putting out 14 v. I do seem to remember this happened to me before and changing the remote fob battery seemed to fix it but it may just have been coincidence
It's working fine now
Well, taking the latch out is easier with the window up and small hands. Take the battery off as you don’t want to loose fingers if the window comes down. Safety first. You sound handy with a wrench though. So, with Rev Sam’s video, note there’s a minor error in the vertical link he broke. The plastic sleeve just slides off the link and you can seperate the two parts of the joint. So get to it.
If you’re changing the latch’s microswitches, do all of them. Problem is how to attach the replacements in the unit - rivets? Forum members have mentioned ingenious methods using glued ear bud stems etc.
Good luck and let us know what you find.
Thanks David
I'm definitely in 2 minds whether to pull the trigger on this yet. I don't seem to have any of the other issues of failed microswitches. The windows drop down when the doors are opened and go back up when closed. The courtesy lights come on and go off as they should and the " door open" warning comes on the dash when either door is opened and goes out when closed. As I type the locks are working to spec. I came across an earlier post where someone had success with lubricating the latch so I've just liberally sprayed WD40 into both.
The same thread gave a link to the microswitches (Mouser) and they are still available. I assume that all 3 switches in the latch are the same?
My wife's 2006 XK8 had the same symptoms (intermittently) from July 2018 until Wayne (cjd777) and I finally replaced the door latch assembly microswitches in early April 2019. That action completely solved the problem. Prior to microswitch replacement I was using the ol' squirt-it-with-WD40 trick. That would solve the issue for a few weeks to as long as a couple of months, but it was always temporary....
In addition to the intermittent open/close door lock cycling, the doors would sometimes lock by themselves with her in the drivers seat and refuse to unlock for her as she pulled on the interior door handle, essentially trapping her in the car and making her very afraid to drive it. Whenever this happened, I could walk outside with my XK8 key fob, approach the car, press the unlock button once, and the door would magically unlock and open for her. That system unfortunately does not work if she happens to be 500 miles away from home (or even 5 miles away from home)....
My wife's 2006 XK8 had the same symptoms (intermittently) from July 2018 until Wayne (cjd777) and I finally replaced the door latch assembly microswitches in early April 2019. That action completely solved the problem. Prior to microswitch replacement I was using the ol' squirt-it-with-WD40 trick. That would solve the issue for a few weeks to as long as a couple of months, but it was always temporary....
In addition to the intermittent open/close door lock cycling, the doors would sometimes lock by themselves with her in the drivers seat and refuse to unlock for her as she pulled on the interior door handle, essentially trapping her in the car and making her very afraid to drive it. Whenever this happened, I could walk outside with my XK8 key fob, approach the car, press the unlock button once, and the door would magically unlock and open for her. That system unfortunately does not work if she happens to be 500 miles away from home (or even 5 miles away from home)....
Good luck with your repair and keep us posted....
Yikes! A very scary situation.
Thanks very much for this as it does seem full replacement of all the switches is on the cards for me.
Just found Rev Sam's YouTube video on door latch removal so I'm good.
Originally Posted by DavidYau
..... with Rev Sam’s video, note there’s a minor error in the vertical link he broke. The plastic sleeve just slides off the link and you can seperate the two parts of the joint. ......
Here's how the link SHOULD be split - NOT forced out and broken:
Slide the black collar down
pop the metal top link out of the plastic bottom half (note the position for refitting)
The plastic section (arrowed in blue) stays on the door latch. The link rod (arrowed in red) stays in the vehicle.
So I've bought a used door latch assembly from a breaker on eBay. £65 including cable and door handle in very good condition. Very pleased.
My plan was to replace all the microswitches in this one and replace my failing one. Having removed all the switches a few things arose:
1. They are not all the same. Two are identical with metal spring activator. One has a sliding push activator and the last one has 2 contacts activated by separate rotating cams.
2. It looks nigh on impossible to dismantle them without trashing them.
Having part dismantled the latch, removed all 4 switches and thoroughly cleaned and lubricated all the moving parts with silicone spray and silicone grease all the switches activate/deactivate (click) with ease.
I note one of them activates when the door latch is fully closed and it has to be tightly closed to make the contact. It's only when the latch is hard up against it's stop that the switch clicks which clearly is correct and so I am wondering whether the issue of cycling locks might be related to this one not fully closing and why judicious WD 40 often solves the problem (albeit temporary if sprayed when the latch is in situ.
If I can find a circuit diagram I'll attempt to see if all the switches are making/breaking contact as they should before fitting it to the car but I'm (naively) hopeful that for £65 I might get to sort this pesky problem.
Steve, Jon and I did discover that the adjustment was critical as it touches the cam arm.
Getting the right curve in the newer switches is a problem, as they are a little longer than originals.
On taking the door latch out, turn it around in the door and it comes out easy.
..... If I can find a circuit diagram I'll attempt to see if all the switches are making/breaking contact as they should before fitting it to the car .....
Page from Electrical Guide attached.
It was a lot easier when I did mine. The microswitches were available from Jaguar back then.
Having removed all the switches a few things arose:
1. They are not all the same. Two are identical with metal spring activator. One has a sliding push activator and the last one has 2 contacts activated by separate rotating cams.
2. It looks nigh on impossible to dismantle them without trashing them.
Having part dismantled the latch, removed all 4 switches and thoroughly cleaned and lubricated all the moving parts with silicone spray and silicone grease all the switches activate/deactivate (click) with ease.
Steve,
Did you happen to take any pics of the unit on the work bench? Would be good to add to this thread, for members in the future.
Just finished repairing my friend's BMW E90 door latches, and he took a lot of photos esp. on how the units have to be initially set up before installing.
Did you happen to take any pics of the unit on the work bench? Would be good to add to this thread, for members in the future.
Just finished repairing my friend's BMW E90 door latches, and he took a lot of photos esp. on how the units have to be initially set up before installing.
Hello David.
I didn't take any photos as most of the time my fingers were covered in silicone spray and grease :-( but I can revisit.
I found the trickiest thing to work out was how to remove the black plastic cover from the latch assembly. There is a lug on the inside of the cover just below the cable entry point on top. You need to wiggle a large blade screwdriver between the cover and latch beside the cable entry and pry out the lug from the latch and it just pops off.
Once off getting to the switches is straightforward and easy to work out. It helps to spray with WD 40 beforehand - they will pop out with the help of a thin flat blade screw driver. You know all this as you've already done it of course.
A few photos to show latch. Use a flat blade screwdriver to pop out the lug holding the plastic cover and remove the screw circled in red and slide cover off. It's not necessary to remove the processor unit bit if you do be sure to re engage the latch circled in red in last photo before putting the cover back. All the 4 microswitches are now easily seen. I removed all except the one circled in blue as I reckoned I'd either break it and/or not be able to realign it correctly. I sprayed all moving parts with silicone spray and lubricated all cams and plastic sliders with silicone grease. All the switches should click on an off easily and with minimal pressure. Pop out the plastic lug here Remove this screw Slide off cover to expose latch and switches Be sure to ensure this is engaged before putting cover back
06-25-2020, 07:58 AM
Door locks keep cycling open and closed
