hi. This may sound tricky but if I did it so can you.
The 4 motors are located under the front of the seat. Undo the top 2 screws of the plate covering them, the 1 nearest the trans. tunnel is the hardest, and swing down. Then pivot the top motor forwards so that the worm drive cables can be pulled out of the motor, you shouldn`t have to undo the locking ferrules. Then get 2 electric drills, 1 will need to have reverse, and attach to the worm drives. It is a matter of trial and error which has to go in reverse but its easy to see which way the seat is trying to move. If you dont put 1 in reverse then the seat tries to move forward on 1 runner and back on the other.
If my memory is right the lower motor moves the whole seat up or down, if you move it all the way up you can undo the connector to the motor, blue block on mine, then by applying a +ve feed to 1 of the paired teminals and -ve to the other you can power the seat into the best position. I left the block undone so that its just a question of reconnecting if I need to move it again. Trial and error to see which pair of terminals have which function, if it goes the wrong way ie up not down then reverse the +ve and -ve feeds to the block. Don`t forget to reassemble the motor before doing this.
hope that helps, let me know?