DIAGNOSIS The charging contacts are corroded or misaligned. Dirty contacts prevent electrical connection.
FIX Unplug the base. Clean the two metal charging pins on the base's front ramp with a pencil eraser or isopropyl alcohol on a cotton swab. On the robot, clean the two metal charging contacts on its rear bumper. Ensure no debris is on the ramp.
IF THAT DIDN'T WORK The base's internal power supply may have failed. Test by plugging the base into a different outlet with a different cable. If the base light remains off, the base is faulty.
HEADS UP Mop kits can drip water onto the contacts. Always remove the mopping pad and plate before docking the robot for charging.