Sensors are safety mechanisms that are designed to prevent the garage door from closing in on a person or object. Once the sensors detect that there is something in the doorway, the garage doors will not close.
The sensors are designed with photo eyes that must be properly aligned or ‘must see each other’ in order for the garage door to close. If these sensors are misaligned or obstructed such that they are not directly aligned, the doors will work in reverse often closing instead of opening all the way down.
If your garage door is not closing, check to see whether the sensors are properly aligned. If they are not aligned, use your hands to adjust them until they are properly aligned. When doing this, also check that there is nothing obstructing the sensors’ LED light. You can clean the sensors using a clean piece of cloth or even an ear bud.
If the sensors are clean and properly aligned buts still not working, check the wires just to make sure that they are not broken. If the problem still persists, there is a last test you can perform so that you can be sure that the sensors are working fine.
Block the sensors and hold or push down the control button on the wall. The doors should close as pressing down the control button usually overrides the sensors. If the garage door still doesn’t close, then something is definitely wrong with the sensors.