clk seat belt extender

[x332race]

I am still having problems with the drivers side seat belt extender and have no undertaken a series of tests. Basically the extender wont extend!

No fault codes
Seat belt buckle on seat seems to be working
Have bench tested the motor in the arm and this is working.
Have tested the micro switch in the arm and this is working
Have checked the fuse and this is ok

As far as I can tell using a multimeter, there is no power getting to the motor....this must thus be due to a problem with the control unit or a relay (if there is one).

Can anyone tell me where the control unit is located?
Can anyone tell me if there is a relay and where it might be located?
Any other suggestions?

 

[AndyPCD]

What machine did you use to check for fault codes as some diagnostic equipment misses certain codes. Also what control unit did you check for fault codes as the fault codes for the seat belt extenders will be stored in the roof control unit.

It would be best to get the car stuck on a star machine and carry out trouble shooting as it gives you step by step guide for this type of fault

 

[x332race]

What machine did you use to check for fault codes as some diagnostic equipment misses certain codes. Also what control unit did you check for fault codes as the fault codes for the seat belt extenders will be stored in the roof control unit.

It would be best to get the car stuck on a star machine and carry out trouble shooting as it gives you step by step guide for this type of fault

I am not sure what machine was used to check for codes.....all I know is that the car as plugged in under the dash. It was not an MB service centre.

How does one access the roof contol unit and where is it located?

 

[richard]

Did you do the coding update that is needed on some of the CLKs ?

Sadly I can't remember how you do it. Last time I did it it solved the problem the customer was having that meant it would work for a while then pack in

Also, with most of the MB control units, if the unit does not see what it expects connected (such as a bulb or a motor) it never tries to power it (but does log a fault)

Richard

 

[x332race]

Did you do the coding update that is needed on some of the CLKs ?

Sadly I can't remember how you do it. Last time I did it it solved the problem the customer was having that meant it would work for a while then pack in

Also, with most of the MB control units, if the unit does not see what it expects connected (such as a bulb or a motor) it never tries to power it (but does log a fault)

Richard

Dont know if any coding update has been carried out...when woudl that have been done? Mine is a 2004/04 model.

 

[x332race]

Incidentally, for reference, I have found that it is possible to remove the motor from the seat belt extender without having to remove the whole arm itself...this also means that you do not need to remove the seats or the side apnel...access can be obtained simply by removing the leather covered "infill" to the panel which can be done in about 5 mins.....then it is a matter of loosening a couple of fixing bolts and jiggling the motor out...a bit fiddly but can be done....I bench tested my motor and found it to be operating ok so I put it back....

Apart from the Motor, there only appers to be one other electrical part to the extender, a micro switch under the arm itself.

I guess it would be much easier just to take the motor off a new or secondhand part and replace a defective motor than replace the whole arm.