If the garage door closes it indicates that the sensors are not functioning.
Garage door sensors should be tested.
Garage doors may display a variety of symptoms if sensors need attention.
If the sensors are working the garage door should immediately stop closing and return to the open position.
Check for incorrect wiring between the sensors and the garage door opener.
If the garage door fails to stop and crushes the box check the sensor alignment.
In this case check the alignment of the opener or better involve a technician.
If your garage door sensors are clean it could be the alignment or the wiring.
Each of the sensors mounted on the garage door has a led.
Here s what liftmaster suggests.
Verify the wire connections are correct on the garage door opener.
Check the sensors leds.
The latest garage door sensors are technologically advanced and even allow you to control the opening and closing through an app on your smartphone.
Eve works as a certified coding specialist.
Sometimes the sensor may be beyond repair due to wear and tear and in such a case your best bet is to replace the garage door sensor with a new one.
However if the door goes back to the open position then the sensors are working as they should.
The second line of defense is a set of infrared sensors which should be mounted 4 to 6 above the floor on each side of the garage door frame.