Passenger door lock issues
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S550
Passenger door lock issues
I recently had to replace the passenger side outside mirror. I found one at a salvage yard in the same color and replaced it with some struggles but when I got everything back together I found that I must have messed up something. Several things are occuring:
Any ideas on what could be wrong?
- See video - door lock stutters when locking.
- Door closure no longer works.
- When outside handle is pulled without the key fob the alarm immediately comes on.
Any ideas on what could be wrong?
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It sounds like you've damaged the door latch mechanism. That unit is the brain for the lock motor, door closure, and handle sensor. When you were struggling with the mirror, you likely forced something that broke the latch internals. The stuttering lock and immediate alarm are classic symptoms of a failed latch. You'll probably need to replace the door latch assembly.
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how did you do the mirror - leaving the entire door trim in place?
either way did you disturb other connectors on the door module - start there
second hand mirrors are often dead from to much pointless folding snapping the wires - and destroying its gears folding from no reason at all
either way did you disturb other connectors on the door module - start there
second hand mirrors are often dead from to much pointless folding snapping the wires - and destroying its gears folding from no reason at all
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just plug back in the old mirror - should take less than 6 mins - and see how the car behaves - there's a massive trim flap that is hidden when the door's closed - it lets you reach the door module wires
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I plugged the old one in with the same result and also checked all of the connections. Alexie suggested the door latch mechanism may have been damaged. Is that also called the door control unit? Could that be the problem? I hate to just keep trying parts. Control unit is $175 so cost isn't bad if that's the problem.
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if you have keyless go the door handle is some super fragile likes to fail, costly catastrophe, it has these super fine antenna wires you don't want to mess with - you never need to pull the door trim off to do the mirrors
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the box of tricks the mirror wires (both multiplugs) plug into is the door control module
its is nothing to do with the door handle its the opposite end of the door.... you could try and check for errors or some muddle up of the door module - but not sure what you could have confused
did some halfwit with Xentry start playing with the door module coding ?
its is nothing to do with the door handle its the opposite end of the door.... you could try and check for errors or some muddle up of the door module - but not sure what you could have confused
did some halfwit with Xentry start playing with the door module coding ?
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Thread Starter
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Joined: Jan 2014
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S550
the box of tricks the mirror wires (both multiplugs) plug into is the door control module
its is nothing to do with the door handle its the opposite end of the door.... you could try and check for errors or some muddle up of the door module - but not sure what you could have confused
did some halfwit with Xentry start playing with the door module coding ?
its is nothing to do with the door handle its the opposite end of the door.... you could try and check for errors or some muddle up of the door module - but not sure what you could have confused
did some halfwit with Xentry start playing with the door module coding ?
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did you unplug something else to get easier access to the mirror multiplugs - and have forgotten to plug it back in ? there's about 5 things plugged in if I remember and or you haven't got things in the right place - but I think they are idiot proof from which plug fits where - worth looking and a quick check vs the other door ?
I believe everything is plug and play the coding shouldn't get muddled or just change - I doubt the door module is wrong - much more likely the handle got damaged or something's not re connected
you have still to answer if you took the door trim off - if you did maybe you dislodged or forgot to connect something, and or damaged the handle somehow
is the mirror behaving correctly ? but now you have lots of unconnected issues with the keyless mess up ?
terminology used might not add clarity - most use the tern door closing to refer to "soft close" its an option and is very different to door locking
do you have the keyless theft option ? this is fragile and can become troublesome as the car ages - three elements to this bit ( but I'm not and expert - mate has it and every other week its in the shop for new parts and odd failures) 1) door control module 2) the delicate door handle and 3) maybe various switches inside the door latch
the door lock stuttering looks like the (pointless) drive away self locking isn't managing to work - have you tried conventionally using the door locks and it all does what it should ?
the alarm going off touching the handle sounds a bit like some thing is muddled
I believe everything is plug and play the coding shouldn't get muddled or just change - I doubt the door module is wrong - much more likely the handle got damaged or something's not re connected
you have still to answer if you took the door trim off - if you did maybe you dislodged or forgot to connect something, and or damaged the handle somehow
is the mirror behaving correctly ? but now you have lots of unconnected issues with the keyless mess up ?
terminology used might not add clarity - most use the tern door closing to refer to "soft close" its an option and is very different to door locking
do you have the keyless theft option ? this is fragile and can become troublesome as the car ages - three elements to this bit ( but I'm not and expert - mate has it and every other week its in the shop for new parts and odd failures) 1) door control module 2) the delicate door handle and 3) maybe various switches inside the door latch
the door lock stuttering looks like the (pointless) drive away self locking isn't managing to work - have you tried conventionally using the door locks and it all does what it should ?
the alarm going off touching the handle sounds a bit like some thing is muddled
Last edited by BOTUS; Sep 26, 2025 at 06:47 AM.
Thread Starter
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S550
I took the door trim off - I couldn't reach the mirror plugs without taking the panel off. I went through everything again yesterday and all connections are in place. I reinstalled the old mirror and had the same result so I don't believe it's in the mirror.
I don't have the keyless theft option.
I won't be able to work on it until this afternoon and will check out your suggestions.
Thank you for your help.
I don't have the keyless theft option.
I won't be able to work on it until this afternoon and will check out your suggestions.
Thank you for your help.
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S550
Still same problems
did you unplug something else to get easier access to the mirror multiplugs - and have forgotten to plug it back in ? there's about 5 things plugged in if I remember and or you haven't got things in the right place - but I think they are idiot proof from which plug fits where - worth looking and a quick check vs the other door ?
I believe everything is plug and play the coding shouldn't get muddled or just change - I doubt the door module is wrong - much more likely the handle got damaged or something's not re connected
you have still to answer if you took the door trim off - if you did maybe you dislodged or forgot to connect something, and or damaged the handle somehow
is the mirror behaving correctly ? but now you have lots of unconnected issues with the keyless mess up ?
terminology used might not add clarity - most use the tern door closing to refer to "soft close" its an option and is very different to door locking
do you have the keyless theft option ? this is fragile and can become troublesome as the car ages - three elements to this bit ( but I'm not and expert - mate has it and every other week its in the shop for new parts and odd failures) 1) door control module 2) the delicate door handle and 3) maybe various switches inside the door latch
the door lock stuttering looks like the (pointless) drive away self locking isn't managing to work - have you tried conventionally using the door locks and it all does what it should ?
the alarm going off touching the handle sounds a bit like some thing is muddled
I believe everything is plug and play the coding shouldn't get muddled or just change - I doubt the door module is wrong - much more likely the handle got damaged or something's not re connected
you have still to answer if you took the door trim off - if you did maybe you dislodged or forgot to connect something, and or damaged the handle somehow
is the mirror behaving correctly ? but now you have lots of unconnected issues with the keyless mess up ?
terminology used might not add clarity - most use the tern door closing to refer to "soft close" its an option and is very different to door locking
do you have the keyless theft option ? this is fragile and can become troublesome as the car ages - three elements to this bit ( but I'm not and expert - mate has it and every other week its in the shop for new parts and odd failures) 1) door control module 2) the delicate door handle and 3) maybe various switches inside the door latch
the door lock stuttering looks like the (pointless) drive away self locking isn't managing to work - have you tried conventionally using the door locks and it all does what it should ?
the alarm going off touching the handle sounds a bit like some thing is muddled
To restate the problems are:
1. Soft close does not work.
2. Door lock stuttering either using the fey for, button or auto lock.
3. Alarm goes off when pulling the door handle.
4. Passenger door does not lock.
I apparently damaged something when I pulled it apart. Is it the door handle? Some module in the door? I've learned that this vehicle is much too complicated for someone of my limited skills!!
ANy suggestions?
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...if all times you never pulled off the inner steel panel - not sure how - but all those appear to be the car not correctly understanding the is door closed correctly - the door lock must have micro switches or such, to know which position the lock catch is in - sounds like its confused
you shouldn’t attempt to work on ANY modern car without high end diagnostic tools - half the time if an error shows "by mistake" the car won't get over itself
AKA to fix anything they want you to go to a dealer and pay $250 to reset its ant brain from robbery mode
I do not propose you try that - as they will uncover / create more issues and costs will go up and they will not fix anything...
you shouldn’t attempt to work on ANY modern car without high end diagnostic tools - half the time if an error shows "by mistake" the car won't get over itself
AKA to fix anything they want you to go to a dealer and pay $250 to reset its ant brain from robbery mode
I do not propose you try that - as they will uncover / create more issues and costs will go up and they will not fix anything...
Last edited by BOTUS; Oct 12, 2025 at 05:15 AM.
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
I once again went through everything yesterday, removed the inside upholstered door panel, checked all of the connections, tried all of your suggestions and the problem still exists. I checked all connections and they are all OK. The mirror functions are OK. I did not remove the intside steel door panel.
To restate the problems are:
1. Soft close does not work.
2. Door lock stuttering either using the fey for, button or auto lock.
3. Alarm goes off when pulling the door handle.
4. Passenger door does not lock.
I apparently damaged something when I pulled it apart. Is it the door handle? Some module in the door? I've learned that this vehicle is much too complicated for someone of my limited skills!!
ANy suggestions?
To restate the problems are:
1. Soft close does not work.
2. Door lock stuttering either using the fey for, button or auto lock.
3. Alarm goes off when pulling the door handle.
4. Passenger door does not lock.
I apparently damaged something when I pulled it apart. Is it the door handle? Some module in the door? I've learned that this vehicle is much too complicated for someone of my limited skills!!
ANy suggestions?
I don’t know why it would make the lock stutter, but the soft close not working points to it as it needs to see door almost closed before it pulls door shut.
Also, from your posts I understand you have checked the connections you had to do for the mirror but did not go to the lock. Perhaps there is a wire connection that got pulled while you worked on the mirror and now has no or bad connection.
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After my last post in October I was at the point that I could live with the annoyance and did nothing. After a few days the lock stuttering stopped and now everything seems to be working properly - it seems to have cured itself! No idea what happened.
Thanks for all of the feedback!
Thanks for all of the feedback!
