Doityourself has a wonderful explanation.
Garage door laser problems.
If you have a problem with your wall switch being unable to open or close the garage door then it s often a problem somewhere in the power supply.
Garage doors may display a.
A common cause of a malfunctioning garage door sensor is lack of power supply.
Knowing how a garage door sensor works allows a homeowner to be watchful for what might affect it.
You ll need to first equip yourself with a wrench of some sort and a tape measure.
A garage door that refuses to close even when the path is clear or a door that starts and stops randomly may indicate a malfunction with the safety sensor.
Look for small led lights on the sensors.
If you do not see a solid illumination or your garage door is not working the problem is most likely due to the sensors being out of line.
If they re turned on in both the sensors then there is no issue with the power supply.
If you find the lights turned off in one or both the sensors it indicates that there is a problem in power supply.
The garage door sensor yellow light and the green light together create a solid illumination.
How a garage door sensor works.
The sensors are located above the floor at each side of the door opening and generate a low voltage beam that completes the electrical circuit when the door is activated.