B200 W245 Door lock problem

[mattwhi]

Hi I have recently bought a 55 reg B200 CDI.

This is my first Mercedes and the car is fantastic.

But it has got a problem with the central locking, sometimes it works then it will start playing up.

When the doors lock at 15mph they will start clicking like they are trying to lock again they click twice then stop for a minute then start again, this goes on for the whole journey.

I have tried with both the auto lock switched on and off, also the door buttons will work sometimes, but while this problem is happening they seem to be disabled.

Also I got out of the car the other day and went to get my 12 week old daughter out of the back and as soon as I got out of the car the doors locked themselves immediately, luckily I had the keys in my hand to unlock again, which they did I managed to get in to get my daughter then the doors locked themselves again and the key button stopped working for a while.

At first I thought could be a sticky solenoid, but it can't be.

Its as though something is constantly telling the doors to lock even though they are.

Anyone any ideas?

(BTW This is my first post I have searched for similar problems but cannot find anything in the forums).

Thank you,

 

[bigtwin]

Usual poor quality MB build. Search bouncing locks for 1,000s of examples and what do do about it.

 

[mattwhi]

The locks are not jumping or bouncing, they are locking, then you can hear them continuing to try and lock, the other posts mention the locks unlocking and locking rapidly.

Does anyone know where the fuse is for the central locking or if they have a relay, I have checked the fuse box but cannot find an associated fuse for the central locking, nor am I able to find any kind of wiring diagram for the B Class.