First, check if the mop is plugged into a working outlet. The light should turn on immediately upon plugging the mop in. If the light doesn’t come on, please call us at 1-800-237-7691, Monday - Friday 8 a.m. to 10 p.m., Saturday 9 a.m. to 8 p.m., or Sunday 10 a.m. to 7 p.m. ET. A representative will be ready and waiting to help you out!