I have mercedes benz c class estate 2009 model that has developed a door locking issue.
Mercedes a class rear door wont lock.
Open and close lock to recalibrate.
Now the rear door on the same side has the same problem.
Apply wd 40 or equivalent product directly into the lock.
On those models the door lock actuators may fail causing the door lock to bounce up and down several times.
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.
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.
Perhaps your mercedes locks work but they open and close slowly.
You likely have a shorted door lock actuator which you can replace with a new unit for the lock that is not working.
Frosty149 sep 20 2017 5.
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.
Try the battery disconnect again maybe a few times.
It does not work with either the central locking or auto lock on movement of the vehicle.
If a door unlocks but will not lock again then replace the door switch.
I have been quoted 1000 at the mercedes main dealer so wanted to know if anyone had any advice on what it could be before i commit to spending that much.
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 took it to a mercedes benz specialist and they said it could be a door actuator.
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.
Rear door wont open on my 2009 200 c class the above link says it can be removed with the door shut.
It seems to only play up once a month or so but now the front.
There is a couple of ways to fix this problem.