The LEDs on both the sending and receiving sensors will glow steadily when the wiring connections and alignment are correct. The amber LED on the sending sensor will glow regardless of alignment or obstruction. If the green LED on the receiving sensor is off, dim, or flickering (and the invisible light beam path is not obstructed), alignment is required.
Note: On the older safety sensors, both LED lights are green. The receiving sensor is the one where the green light goes out when you pass your hand in front of the sensor. The sending sensor stays solid.
Remove the receiving sensor (green LED) from bracket. You can do so by taking off the wing nut.
Point the sensor away from the sending sensor so that the LED light is completely off.
Once the LED light is off, wait 10 seconds.
Slowly rotate sensor back until it lights again. When you have a strong green light, put it back into the bracket and put the wing nut back on.