"The Igloo 100 series portable icemakers that are sold all over for about $100 have several minor issues. For ADD WATER light, there are 2 main ones. The water SENSOR is located at the top right of the unit. Remove the BACK cover with 6 screws on the bottom. Remove the TOP assy with 4 screws from inside the case. When the TOP is off, facing the unit from front, you see the small silver wire at the back right. Clean it AND the screw visible thru the hole in the plastic at the end of the sensor wire. The screw is the GROUND side of the sensor. This fixes many of the issues. But the SENSOR senses water FLOW, not water LEVEL. If the PUMP is not moving water, the sensor assumes you are OUT of water and turns on the ADD WATER light. The pump apparently burns out easily. Remove the PUMP wire connector from the CONTROL BOARD and check for continuity in the motor. Be sure your multimeter leads actually touch the connectors. The connection end is too small for most meters, so probe from the backside of the connector. If motor is good, check for 12vdc at the board side of the pump connector. Plug in, turn on. Should be 12vdc within 45 seconds. See, the water pump comes on first. When water is moving over the sensor, then the board will turn on the compressor and start freezing. "