My 2001 Nissan Altima driver's side seat has all motion except backwards. How can I get it to go backwards?

Before I did anything like spend a lot of money buying any parts .
I would put my head down and look under to seat locate the motor slide it forward useing the motor see what happens when it moves .
If the motor will go in 1 derection most of the time the motor is good and could be a problem with the connection wiggle the connector see if that fixes the problem .If so unplug it and clean the connection.
Also check the track make sure no debrie kitty toys lose change old french fries ECT.
The fuse isn't the problem because it moves in 1 derection listen for the noise the motor makes .So it moves that noise it dosn't move backward is their a noise like the motor wants to move but can't or no noise at all in back mode then now power to motor check connections and switches .
Wiggle the connections most of the you can isolitate problems like this and save paying someone to remove that seat and replace a motor that is likely working as good as the day it rolled off the line .
Investigate it good luck

The backward motor has quit working, go to junk yard and find same car in your year range up or down pay particular attention to how your seat track looks. designs change every three or four years. it must be exact or it will not work.