Heatgun
The Heatgun is a tool in the Firetruck that gives you the ability to see all the hot spots in the vicinity. Very handy if you want to find the fire quickly when it is not directly visible.
How to use
You can pick it up by reaching for it, which will highlight it, and pressing the trigger button on your controller. It will then be put in your hand. Then it is a matter of pointing it at the place you want to check for a possible fire and look at the screen.