This page will show you how to repair the common problem of the headrest not going up and down in your BMW. All too often the headrest motor can be heard operating but the headrest doesn't move. This is normally always caused by the cable not engaging with the headrest socket/gear. There are two ways to fix without buying a new cable. Cutting the outer sheath and splicing it together or dropping a small piece of plastic or wire into the motor socket. I will show you the latter since I believe this is the easiest.
I know other websites disagree with this method and warn against doing it this way but they also fail to fully understand what is going on. Some of the websites state that the cable sheath stretches from usage. This is not true. The cable sheath does not carry the torque from the motor, it merely carries the cable and prevents it from twisting out of the drive sockets. The inside cable is what takes the torque from the motor and shrinks or shortens with age. For example take a string and twist the ends in opposite directions you will see that it gets shorter in length. Same thing applies here, the cable shortens over years of usage.
Repairs can be done either way. By cutting and shortening the cable sheath this actually brings the motor and cable closer to the headrest gear. So yes it will work but seems like more work to cut and disassemble cable and risk cutting yourself. You'll also have to purchase hose clamps and a hose. BMW's such as the M6 will need to be done by cutting the cable since they tend to disengage at the headrest gear at the motor.
To do my easier method start by undoing the four screws that hold the back panel then pull the panel down and out towards you. Below is what you will see inside the seat.
Undo the two bolts (as shown below) for the motor that attach it to the frame and remove it. Next simply pull the cable and sheath out.
Get yourself a coat hanger or plastic tubing from a spray can of carburator cleaner or brake cleaner and cut off 1/4-3/8" of it. Then drop it into the drive cable socket and replace the cable. You may now reinstall the motor and test it. The headrest should now go up and down. (Sounds too easy, doesn't it?) If it works you can put the back panel back on and you're done.
So what happened here? This method pushes the cable towards the headrest gear allowing it to engage the gear. Usually 1/4-3/8" is enough. If it doesn't work, then cut a longer piece to drop into the drive socket. Don't make it too long-- just make it long enough to make the cable engage the socket. If it's too long it will not engage with the drive socket.
In the pictures below you can see the piece of plastic I placed inside the drive socket it's the dark reddish piece inside. This piece has been there for 7 years. Even before I wrote an article that was in the Tech section of the May 1995 Roundel, without any problem. This Plastic or wire just sits in the socket and turns with the socket and cable it does not actually go into the motor or get ground up as some others seem to suggest.
Any way I hope this repair worked for you and gave you a better understanding of how it works.
If you prefer to do the splicing of the cable sheath here is one of the other websites besides mine: http://silverstone.fortunecity.com/ferrari/464/front1.htm
Happy motoring,
©2002 Winston Fong
