The answer to 'why is my carbon monoxide detector flickering lights' is that a flickering or blinking light on a carbon monoxide (CO) detector is a common indication that the device is functioning properly and detecting normal levels of CO in the air. This blinking light is a normal operational feature designed to let you know the detector is active and monitoring for dangerous CO gas.
However, if the light is blinking rapidly or the detector is sounding an alarm, that could mean elevated CO levels in your home. This requires immediate action to identify and eliminate the CO source, which may involve calling a professional HVAC technician to inspect your furnace, water heater, or other appliances that burn fossil fuels.