The red light on the control panel of your Portacool evaporative cooler next to the pump switch is actually a low-level light. When the product is full of water, the light should not be illuminated. If the light is on, it means your cooler is out of water and the pump has shut off to protect itself from failure. When the cooler is refilled the light should turn off. The light should not be on when the cooler has the appropriate level of water.