If the switch doesn't work forewards but does backwards then reverse the polarity to the seat if you can.
Otherwise take 2 jumper wires from the cig lighter or some fused supply and jump the motors directlym they are under the front of each seat.
You can take out the drive cables and spin those but it takes forever and you can't guarantee spinning them both the same amount.
If it's one motor that's given up (rare) then swap the cables to a motor that does work and use that.
