PA Power Seat problem

My '99 PA passenger seat goes fwd and backward but is stuck at the "high" position. I can hear the motor turn, but there is no movement. The seat undercarriage is clear. Any suggestions?

My '99 PA passenger seat goes fwd and backward but is stuck at the "high" position. I can hear the motor turn, but there is no movement. The seat undercarriage is clear. Any suggestions?
I have the same problem just it's stuck at the 'low' position. Took it to mechanics, they say there's some defect in vertical adjuster motor. Although it turns, no movement is being transfered to the gear. Probably, some gear inside motor itself is broken. Motor needs to be replaced. Unfortunately, no luck so far in finding it. Do they sell these motors separately at all? Would appreciate any suggestions on this matter.

I was unable to find the individual motors (there was 4 on my seat), but was able to purchase the seat track assembly (then just transferred the motor I needed). Check car-part.com, search for "seat track." They have businesses listed there that sell the assembly for $200 and less. I purchased a brand new assembly for just under $200-shipping included ( New ones from Buick dealers were around $1000). Another option is to go under the seat and move the mechanism manually to a position you are happy with...I'm pretty sure this can be done, but I just replaced the motor. I've yet to take the old motor apart to see if something is actually broken or something just slipped out of place. Fixed driver's side- now a motor is out on the passenger side...seems to be a common problem, but fixing it yourself saves money!