The difficulty level of this DIY is a level
2 in a scale level of 1-10
When the power seats fails to move forward and backward in a 993 it is most likily either a bad switch or a stripped flexible drive shaft. This DIY will focus on how to replace the flexible drive shaft.
(6). Install the new shaft and line it
up with the motor drive gear, you may need to tap on the power seat switch
to get the square notch to line up while you install the shaft to the motor.
When installing the shaft to the seat's drive gear make sure that it is
pluged all the way in, you may even want to turn the shaft with your fingers
to make sure it is mounted correctly before attaching it to the motor.