If you are unsure whether or not your vehicle currently has a rain sensor system installed, the easiest way to tell is if you ever notice your wipers starting automatically. 

What rain sensors are designed to do is to detect moisture and if needed wipe away the water so you can focus on the road with a clear view. Also, if your car has rain sensors installed, you will notice a square panel mounted on the windshield near the rearview mirror.

For the most part rain sensors do work similar to light sensors in that the goal is to help increase safety and take out chances of human negligence. As the windshield deducts moisture levels, the wiper blades will automatically kick in to give the driver a clear view of the road without having to manually engage the wiper blades.

Cracks in the windshield can disrupt or altogether cause a massive malfunction in the rain sensor system. It may cause the wipers to kick in without having any rain drops or fail to auto-start the wipers when needed. 

When having your windshield replaced be sure to the new windshield comes with the same rain sensor technology included in your manufacturer's windshield when you bought the car.

It's important to get as much information as possible and educate yourself on all the advanced windshield technologies available on today's cars. That way if something happens to your windshield, you are aware of the technology and can be sure that your new windshield comes with all the same features.