Now the rear door on the same side has the same problem.
Mercedes a class rear door wont lock.
It seems to only play up once a month or so but now the front.
Try the battery disconnect again maybe a few times.
There is a couple of ways to fix this problem.
Open and close lock to recalibrate.
Perhaps your mercedes locks work but they open and close slowly.
Rear door wont open on my 2009 200 c class the above link says it can be removed with the door shut.
First you can replace the door lock actuator which can cost from 150 to 450 depending on if you try to fix it yourself or have the dealer fix the problem.
This issue is a failure of the internal door lock actuator which is failed in the lock position which is causing the door not to open.
If a door unlocks but will not lock again then replace the door switch.
If your car door lock actuator is not working properly a common problem is that the plastic air reservoir at the bottom of the actuator is broken or crack.
I took it to a mercedes benz specialist and they said it could be a door actuator.
Our local mechanic couldn t identify a problem.
See also mercedes benz w204 rear door panel removal 2008 2014 c250 c300 c350 pelican parts diy maintenance article and w204 rear door panel removal google search dec.
Frosty149 sep 20 2017 5.
Have a look at yours first it could be a simple connection issue at the lock or where the wires go from the door to the main body chassis otherwise you may just be throwing away cash.
Apply wd 40 or equivalent product directly into the lock.
The actuator will have to be replaced which will require the door panel to be removed and with the door closed this won t be easy and needs to be done by a garage or dealer that has done this before.
On those models the door lock actuators may fail causing the door lock to bounce up and down several times.
It has to be manually locked and released.
Earlier this year the driver s door would occasionally not open unless i pressed the key fob repeatedly.
I have mercedes benz c class estate 2009 model that has developed a door locking issue.