It is a common fault on these vehicles for a small spring within the door lock actuator to snap causing the symptoms noted.
Mercedes a class door lock fault.
3rd generation mercedes benz c class door lock fault since the mid 1990 s german auto manufacturer mercedes has impressed the luxury car forum with its c class series.
Perhaps your mercedes locks work but they open and close slowly.
If a door unlocks but will not lock again then replace the door switch.
If you are finding it difficult to open the rear hatch then it is due to a problem with the boot lock.
There is a couple of ways to fix this problem.
The boot catch is known for sticking on the a class.
On those models the door lock actuators may fail causing the door lock to bounce up and down several times.
Details about mercedes c class w203 2000 2007 door latch actuators repair kit spring x2.
Door lock jumping up and down quickly door not locking or only periodically door lock rattles.
Mercedes benz vehicles such as e c s ml gl r class are designed to automatically lock the doors as soon as you start to drive.
You likely have a shorted door lock actuator which you can replace with a new unit for the lock that is not working.
Once you start to notice this niggle it might be sensible to sort it immediately as if the boot lock fails and you can t access the boot it could be very inconvenient.