The powered headrest on my 99 C280 has a mind of its own. when I press the button on the door to either lift or lower it, it works and sometimes it doesn't. If I hit the seat a couple of times with my fist it will work. I have taken off the back seat panel and find there is something loose, it seems to be a connections to the motor. BUT I have no idea on how to tighten it. It is a plastic connector and if I push it into the blades the headrest works, but the circuit is broken as soon as I put the back cover on. I have checked for pinched or pulled wires. However, the problem seems to be at the connector.

I also noticed is I take the weight of of my shoulders off the back of the seat, sometimes the headrest will work?

The passenger side works fine.

Thanks!

 

Did u try cleaning the terminals on the connector?

 

confirm first if it's mechanical (gear strip) or electrical (motor working or not).