I just had this problem happen to me a few weeks ago. My 01 SCREW adjustable pedals suddenly stopped working. The only thing I get is about a 1/2 in movement up or down when I hit the button, and after that 1/2 movement the motor just stops running, this happens in either direction, so I don't think its the worm gear. Seems more like the pedals are stuck, not sure what is causing the motor to just stop running after the slight movement. Naturally, the pedals are stuck in the highest position.

 

A 40 amp maxi fuse feeds the motor switch as well as power seats if you have the them.
If the pedal assembly moves at all, look under the dash for something wound up on the lead screw.
Good luck.