I have two regents motion sensor lights on opposite sides of the house. When I put power to them they stay on constant. I've checked the mode and sensitivity switches and they seem fine. I cleaned the outside of the sensors with windex on a rag. Lights still stay on. The motion sensors are about ten years old. I am not the original owner of the home that put the lights up and I don't have a manual for the lights. I was hoping to figure out how to take the sensors apart for a through cleaning but I don't want to break them. Can I just buy two new sensors? If so what are the best, for price, durability and energy efficiency.