FAQ Search Select a Category Cleaning Formulas Cleaning Tips Commercial Products Corporate Deep Cleaners Hard Floor Cleaners Mops, Brooms and Brushes Parts and Accessories Steam Sweepers Vacuums Warranty Web Site and/or go What is the purpose of the Clean Carpet Sensor? Answer: The Clean Carpet Sensor on models #3594 and #3594-M will detect dirt or debris being picked up while vacuuming. The sensor will show red when dirt and debris is being suctioned and will show green when the carpet is clean of debris. Related Questions Why is my vacuum sounding loud? What should I check? Why is the brush roll on my Lift-Off® Floors & More not turning? The brush on my Powerlifter® (1307 & 1309 models) is not spinning. What do I check? My AeroSwift® Vacuum has no power. What should I do?