Power seat headrest

[ajay1945]

The electric headrest on my CLK Cab passenger side just stopped working going down, so I can't tilt the seat cos the headrest hits the windscreen. Can anybody suggest where to start looking for the problem? It's on a separate switch to all the other seat functions (which are ok) so is it fused separately or what? All suggestions welcomed!

Cheers,

Ajay.

[SLacKer]

ajay1945 said:

The electric headrest on my CLK Cab passenger side just stopped working going down, so I can't tilt the seat cos the headrest hits the windscreen. Can anybody suggest where to start looking for the problem? It's on a separate switch to all the other seat functions (which are ok) so is it fused separately or what? All suggestions welcomed!

Cheers,

Ajay.

I have a C32 and when I got it the headrest would not work on the drivers side (This was meant to be fixed before I picked it up but for some reason the Merc Garage which did the work - not supplying the car by the way - changed the passenger seat one (which was working)). Anyway I fixed mine as it was a dry joint on the motor in the seat back.

You take off the plastic seat back and then remove the headrest motor and mechanism - it is fiddly to get out but it is not the nightmare it sounds as it is standalone from the rest of the seat motors. I got it on the bench and reflowed the solder on the connector and all now works. Now as I remember there are 3 pins so I guess there is an up, down and ground so if one has failed it may mean that joint is dry.

You can see the connector and if you rock it with your finger you can see if it is a dry joint as you can see the solder points flexing before you take it all apart. The button is not directly wired to the seat as it uses the BUS to signal the headrest to go up or down and it is the bus that signals the seat. If it is a dry joint you could move the connector with one finger to get a circuit then press the switch to lower the headrest and at least get back to normal.

Of course it may be something different but that is what it was for me and the CLK and C class have the same interiors for the most part.

Edited by SLacKer on Thursday 6th May 12:49

[ajay1945]

Thanks for the post SLaCker,

I went to investigate following your instructions, and just decided to check the other seat functions again, before I started. I find now that none of the functions work. I checked the 3 fuses which control the seat, and they all appear to be ok. Any more suggestions please?

Cheers, AJ

[SLacKer]

ajay1945 said:

Thanks for the post SLaCker,

I went to investigate following your instructions, and just decided to check the other seat functions again, before I started. I find now that none of the functions work. I checked the 3 fuses which control the seat, and they all appear to be ok. Any more suggestions please?

Cheers, AJ

Complete seat failure......hmmmmmmmmmm

The fuses check out so the next port of call is check the main power connector under the seat. I think it is the one nearest the centre of the car and has 3 leads on it. Is this in securely as it provides ignition 12v, permanent 12v and earth. If so test the voltage, if ok then it may be a failure of the switch control, seems odd though for it to fail in stages.