Driver seat stopped moving forward or backward electronically

Typically there are three motors, and most of the time their plugs are the same so they can be interchanged. Switch two plugs between the two motors, then see what operates. Two switches will run the wrong functions, but if the "forward / backward" switch makes something move, you'll know that switch is working. If any switch makes the seat move forward and backward, you'll know that motor is okay.

That's the way most mechanics would start the diagnosis since it's a lot faster than dragging out test equipment and searching for a wiring diagram.

You'll have to ask at the dealer's parts department if you can order just a motor or if you have to get the entire seat base. In the past you typically only got an entire seat frame when the car was under warranty and the manufacturer was paying the bill. It's up to them if they want to make parts available for it. A better alternative is to visit a salvage yard for the parts you need. You'll probably pay less for the entire seat base than for just the motor through the dealer. With a used base, you can see how the motors are attached and you can determine how to replace it on your car, possibly without removing the seat from the car.