Question

If the temperature warning light/gauge goes on, what should you do?

Answer 1

The thing that i should do if the temperature warning light/gauge goes on is to stop as soon as you can at a safe place and shut down the engine off. I hope you are satisfied with my answer and feel fee to ask for more if you have question and clarifications 

Answer 2

A. Stop as soon as you can at a safe place and shut the engine off.

You do not need to stop immediately on the side of the road. However, at the closest parking lot or place where you can easily receive roadside assistance would be good. It's important that you do not open the radiator cap to check the water level until the engine cools down. You could be burnt by escaping steam when you take the cap off. Never ignore warning lights. Yes, the light will go off when the engine cools off, but that's only going to happen when the car is off. As soon as you turn the car on and start to drive the warning will return. Warning lights are also color coded. Red warning signals mean a serious problem. Stop and get it fixed immediately. Orange mean that it needs to be addressed quickly but you do not need to stop on the side of the road. Yellow lights are usually about regular service or maintenance that needs to happen. These should not be ignored, but they aren't indicators of a serious malfunction.