Recently got an '01 330ci with sport seats and realized this issue. I tried searching forums and find similar issues, but not this exact problem.

Drivers side seat will go forward but not backward, and up but not down. I can hear it clicking, so I'm guessing the switch works. Thought it might be the motor, so I unplugged the connector to it and used alligator clips and a 12v battery to check, and got it to work, in both directions. So the motors are fine. The fuses (65 and 70) are both good. I don't know what else to check