Thank you for submitting your question. You might have bad door sensors, wiring to the sensors, or the logic board is faulty. If the LED lights on the motor unit or sensors is blinking, the sensors may be misaligned. If either door sensor light is not on, replace the sensors. You can also, check the voltage from the logic board at the sensors, you'll need an ohms/volt meter to do so. With the ohms/volt meter, if don't get a reading of 4-5 volts dc, check the voltage at the logic board with the sensor wires disconnected. If the voltage is incorrect at the terminals the logic board is bad. Check the wiring to the sensors and be sure a staple is not cutting the wire. I hope this information helps. For further assistance, please reply back to this thread with the complete model number of your unit. Thank you for choosing Manage My Life.