I had the same problem when I bought my bike. The radiator cap level was full. Then I removed the left side cover plate and filled the overflow reservoir with the appropriate mixture. No more light. After running the bike again, light came back on... Reservoir needs to be filled to the line marked. Seems like after running the bike with the reservoir only partially filled, the sensor canĀ“t detect a fluid level at all. My guess is your bike is not overheating.