1999 Chevy Cavalier engine water level sensor

It's connected to your coolant tank of course. Most folks dont actually put water in their coolant tanks, since that leads to harmful and destructive mineral deposits that ruin your engine.

Also if you have any work done to your coolant system in any way, make sure they bled all the air out of the lines, otherwise your sensor will not stop giving you a warning light. That or you just need to replace your sensor. Personally mine shorted out while getting some body work done, no idea how they managed to do it, but they did.

The part costs less then $20 and the labor is less then 30 minutes. Make sure you dont get ripped off.