On your model, one sensor should light yellow (amber) and the other should light green. The "sending" eye is the yellow one. It will remain yellow all the time so you can know that it is sending the signal. The receiving eye will light steady green with it is properly aligned. If both sensors are lighting up yellow, then you have 2 sending sensors and no receiving sensor.
If only the one is lit up yellow and the other is dark, blinking, or flickering then the sensors are just not aligned properly. Again, if both are lit yellow, you do not have a receiving eye and you will need to get one or the unit will not function with the remotes.
Thank you for using Manage My Life!