If the Clean Carpet Sensor is continually flickering or red, you will want to clean the lens of the sensor. Detach the Twist'n Snap Hose at the back of the machine and gently wipe the clear lens area using a lightly dampened soft cloth. Allow enough time for the lens to dry thoroughly before reattaching the hose and using the vacuum. If you need further assistance with this, please take your machine to a local BISSELL Authorized Service Center. To locate your nearest BISSELL Authorized Service Center, go here http://www.bissell.com/support/product-support/service-centers. Enter your zip code to perform your search. You can also locate a Service Center by phone, 24 hours a day, by calling 1-800-237-7691 and choosing option #1.