Turn off the garage door opener
Locate both sensors near the bottom of the door tracks
Check that both sensors face each other directly
Loosen the sensor mounting brackets slightly
Adjust both sensors to the same height
Align the sensor lenses so they point straight at each other
Tighten the mounting brackets
Check for obstructions between the sensors
Inspect and clean the sensor lenses
Verify the sensor indicator lights are steady
Test the garage door opener
Repeat the alignment if the door still will not close