If the quality of the floor cannot be fixed, consider a u-shaped bottom weatherstrip, which can adjust to an uneven surface to create a seal. Another option to consider if the floor is uneven is a garage door seal strip. These can be purchased and applied to the floor to help fill in areas of unevenness.
Each sensor will usually have a light. One will have a green light, used to show that the units are powered up, and the other will have a red light to show that there's no obstruction between the sensors and that they're 'seeing' each other. Feb 12, 2020