ohh, well, we had that already back in 2006
http://www.bimmernut.com/forum/5-ser...-seat-fix.html
To eliminate electric operation:
Pull up on rear seat cover to remove. Observe black plastic sockets riveted to each side of headrest adjustment mechanism where headrest posts snap mount. Pull each headrest post out of the black plastic sockets. Bend both sides of the metal arms forward so headrest posts will clear black plastic sockets. Headrests are now manually adjustable by pulling up or down. Electric not worth the trouble.
To repair defect:
All you have to do is remove the rear of the seat and peel back some of the leather/fabric from the tongs so that you can access the head rest motor on the right side of the seat. Undo the motor's mounting screws that hold the motor and remove it...then unscrew the drive cable from the motor (should be 2 crews that hold the cable in the motor). Take a 1/4" of metal coat hanger (straight) and insert it into the motor (where the cable goes) then re-insert the cable. Test the headrest to see if it works, then put the seat back together. The problem is that the cable sheathing stretches over time and the cable unseats itself from the drive within the motor. The 1/4" piece of metal hanger helps the inner cable to make contact with the drive on both ends. I know this sounds weird but it has worked for me...I did it about 2 years ago on my 7 and it has never failed since.
http://www.nmia.com/~dgnrg/headrest2.jpg
http://www.nmia.com/~dgnrg/headrest1.jpg
these pics are from E32
Another fix is like this
Because it is a worm gear the motor and cable need to engage.
http://www.bimmerboard.com/forums/posts/5326
Good timing. I am about to do this on the sport seats I installed on my 535. The driver's side works fine but the passenger side is stuck on "very tall". Fortunately I have the old comfort seats to strip parts from.
1990 535im 421,000 miles, 1987 325is, 1989 325is, 1990 m3, 1991 318is, 2001 X5 3.0