The part can potentially be fixed!
 

I decided to not just replace the part, but to see if I could stand a chance and actually fix it.
So I followed the good instructions above to take the part out. I'm adding a few pics for that procedure, in hopes this can complement the original set put in by twh.
View from top, just before removal of the plastic "shield":


http://img833.imageshack.us/img833/2356/em3u.jpg

The wire dangling there is likely power supply to the heater. No need to touch it - if you have it there, simply disconnect it (note - there's a clip you'll need to press and then the plug can be easily pulled out):


http://img855.imageshack.us/img855/8527/93wq.jpg

About 10 torx screws need removal for the part to be taken out. Tip - I found it easier to slide the part out after tilting the seat upwards (bottom down / front up):


http://img845.imageshack.us/img845/3064/zvc7.jpg



Now for the part fixing: I realized on first inspection that nothing looked broken. But once I opened the little gearbox, I saw the damage (to open, remove 3 silver torx screws, 3 black ones connecting the motor and carefully pry the plastic clips around the gearbox - do not break them!).


The plastic gear simply snapped, causing the motor to run "on empty":


http://img853.imageshack.us/img853/5084/vaxv.jpg

Top pinion removed:


http://img829.imageshack.us/img829/3269/xnhg.jpg

The two halves of the broken gear. Notice the little "bubble" in each of the halves. I believe this bubble was there when the gear was molded and was probably its "weak spot:"


http://img822.imageshack.us/img822/7076/1xrr.jpg

I decided to attempt and fix this by epoxying the gear back to place. So I carefully cleaned the gear and the connection area with a bit of alcohol:


http://img829.imageshack.us/img829/8083/8he3.jpg

First half on, with epoxy:


http://img845.imageshack.us/img845/5461/njri.jpg

Putting some pressure (not too much, you don't want to damage the "teeth" of the gear). Make sure that no epoxy drips between the teeth. I chose to put some on top as well, in hopes to create as much adherence as possible:


http://img713.imageshack.us/img713/1963/6ni1.jpg

All cured:


http://img855.imageshack.us/img855/2028/f54y.jpg

As you assemble the gearbox back together, make sure to add some fresh grease (don't drown it, just a bit). While I was waiting for the epoxy to cure, I added some grease on the rails as well.




http://img829.imageshack.us/img829/6268/o0gm.jpg

It hold! If you let epoxy dry. I would think it would hold.

Nice work work on the repair! I still haven't repaired mine and was planning on working on my todo list over the next few weeks. I think I'll have a look and see how well it stays once glued. Is the gear a tight fit ? Wasn't sure if it would be better to glue in place or off and then install...

Quick update: A few days after the fix the part still holds nicely. Able to move the cushion in and out full range. All functions, like auto-stop on either end and set memory have been retained.

That was the same part that broken on mine.

If you still have the part, take a quick look on pinion itself. The plastic gear must be molded right onto it during the manufacturing process - it is not "slid into place". It's a very interesting method to combine plastic and metal together.


And I guess it doesn't work too well, since it may be failing for quite a few people/cars.

I don't think it will be possible to glue-first and then "integrate" the gear with the pinion. That's why I also commented that it feels to me that the plastic gear was "molded in place" right onto the pinion.


The section on which the gear is on is narrow, while the edges of the pinion are thicker. A bit hard to explain but you'll see once you take a look.

My guess it would be a press fit but very tight. I am gonna give it a shot over the next weeks. Need to get the riding lawn mower out of the garage first!

More often than not, the thigh support on used 5's and 7's is broken. I've found it very unusual to find a car where both supports are operational.

My driverside has never broken and it's used every day. The passenger side that was broke was caused by my father inlaw. He was a passenger and the thigh extension was extended. He couldn't figure out how to retract it so he basically forced it back thinking this was the way...