[97Bird]

Try spraying some tuner cleaner into the switch that controls the back and forth motion in case the contacts are dirty. Tuner cleaner is available in the electrical/electronic dept of many hardware stores or at Radio Shack. Don't spray the cleaner on the seat or carpet because I don't know if it will remove the color or stain them. The switch is the usual problem. Remove the connector from the motor and connect a digital voltmeter between the two leads of the harness going to that motor. When you press the switch in one direction it should read 12V. When you press the switch in the other direction the meter will read -12V. If you have an analog meter then connect the - lead to a good ground location and with the switch in one direction, one of the two leads going to the motor will show 12V. With the switch in the other direction, the other lead will show 12V. If you get these readings then the switch is functioning. Plug the cable back into the motors and if it still doesn't work then the motor is most likely at fault. You can next remove the motor from the seat track and see if it operates by itself.