Suggest you remove the glass door that is fitted. Simply lift it by it's outer edge and it will come ouit of it's clips. Then remove the shiny black plastic panels that are behind the doors. Best done with a butter knife along the outer edge. They just clip in. This will reveal the sensors which are half way down both outer edges of the main unit.
Does the door mechanism work now? Check that the motor assembly is plugged into the pcb.
If yes, try removing the black tape often found on the inside of the black plastic panels and reassemble.
If no, then your problem is deep seated and best left to a service center.