What is the toyota camry water temp warning light's function?

The function of the water temp warning light in Your Toyota Camry is to alert You when the engine is overheating. It does this by reading the temperature of the coolant as it leaves the engine block. If the coolant is above a certain temp the light will be turned on. An overheating engine is a very serious issue and not one You should ignore or continue to drive the vehicle during. The most common cause of this warning other than lack of coolant in the reservoir is the radiator fan failing to turn. The fan normally comes on at a certain temp and is used to add extra air flow through the radiator when the car is not moving fast enough for the air to be pushed through on its own.