Paul, I posted a lengthy description of the repair about six months ago.
I've also sent out scanned pages of the seat removal process to several list members.
There is a single motor under the front edge of the seat responsible for raising and lowering the seat cushion using two scissor-jacks located on both sides.
When one cable fails, only one jack works and the seat rises unevenly.
The jack gearboxes are located at the back of the seat, and two cables are used to transmit power from the motor to the gearboxes.
The drive cable consists of what looks like a tightly-coiled piano wire inside a protective outer jacket.
For some silly reason, BMW's cables fail due to the inner drive wire shortening inside the fixed outside jacket.
The solution is either shorten the outer jacket (my recommendation), or insert a short length of coat hanger into the end of the motor and reinsert the failed cable (untested, but I've been assured this works).
It's possible to fix the seat in the car, but I prefer to remove it by simply unscrewing the six big T-55 Torx bolts holding the seat rails to the floor and disconnecting the electrical plugs.
Once the seat is removed, simply loosen the failing cable from the motor (two small bolts and a retaining clip), remove the cable and the inner drive wire, carefully work the end fitting loose (hardest part), and strip back about 2 mm of cable using a hacksaw.
Attach the end fitting, reinsert the drive wire, and attach everything to the motor.
Replacing the cable completely is time-consuming since it involves removing a good deal of parts at the rear of the seat.
Furthermore, you'll soon have the same failure as the new cable shortens and disconnects itself from the drive motor.
The shortening procedure is the preferred repair method.
If the dealer understands the problem and will fix it for only $60.00, I'd strongly recommend letting them do it.
Fling, Mark F.
Thanks to Mark Fling's excellent description, I was able to fix my driver's side seat at home this weekend in about and hour.
I did first look at the pass side to see how the San Diego dealer did it.
As Mark wrote, first take the map pocket valence off by unscrewing the two screws after you carefully take the leather pocket off by prying out the five (one on each side by the screws and three on bottom) plastic inserting/gripping buttons.
(the dealer broke one of mine on the pass side so it was super glued and put back).
You will then see the motor with two 'Bowden' cables coming out of each side.
You can determine which one is the offending cable by noticing which side of the seat comes up - that side is the good side/it's working.
By the way, I decided not to take the seat out - it is possible to do it with the seat in place esp.
if you are gone work on the cable that is slightly longer (outer one on my driver's seat) - you will see what I mean when/if you open it up.
The shorter side cable is also attached to electrical cables with a tie so you would have to snap it off before working on the cable.
I didn't have to cause the longer side is without any attachments.
Take the cable out of the motor by undoing one of the two screws on the plate - no need to do both since it will drop off and let the cable out.
One less hassle when you are putting it back.
Pull the greasy cable out and leave where it won't take the grease off -
I then took my Dremel rotary tool and cut the cable sheath/housing about 1 1/2 inch from the end then cut another 1/4 inch or less on which ever side - doesn't matter.
I bought a 5/16th" fuel hose (79cents/foot) and cut about 1 1/2 inch of it and slipped the two sheath into it and clamped them on both side with appropriate size hose clamps ($1.39).
I then put the cable back in - there is a plastic guide ring that may come out with it when you pull the cable out so make sure you put that back in as well...and reattached it back into
the motor and voila, it worked - seat went up and down well with no problem!
EXCEPT, now the seat wouldn't go back and forth - !!!
S so i called Mark in mild panic, who thought I probably had the seat still in torqued/twisted position
I checked the seats visually and sure enough, my seats were way too close to the center console and just not mechanically/physically able to move thru it's range.
With the cable out, i adjusted the seat 'til it looked about levelled/straight and put the cable back in and this time, the back/forth movement was without any catch - nice and smooth!
So, there you have it - it is a very easy fix and if you are not too big to work in that cramped spot, it can be done without taking the seat out!
Again, thanks to Mark.
Here is how you may be able to save approx' $180 if you have a seat motor failure.
My driver’s side seat had no vertical movement, and found that the applicable motor was not working. I was happy that it was possible to re-solder a broken wire connection inside the motor.