Hello, thanks for letting us answer your questions. We appreciate your business!I am afraid that is you have tried cycling the power on and off and the problem persists, you have a shorted relay on the smart board. The computer bypasses the relay when the oven calls for heating, There microswitch on the louver cam notifies the smart board that the louver is open, but the board is is not responding to turn off the louver motor. You only option is to either replace the smart board or disable the motor on the louver mechanism if the microwave functions are still operating.Here is a link for the smart board if you choose to try to repair it. The louver motor is located behind the moving louver on the top of the door.
WB07X10442 part number for louver motor