Have you ever wondered what powers your car's air conditioner? Some things in your car work while the engine's not running, like your headlights. They run off of your car's battery, which is why you can come back to a dead car battery if you accidentally leave your headlights on after you leave your car.

However, your air conditioner won't work with the engine off. Why? It's powered by the serpentine belt that's connected to your engine. The serpentine belt runs only when the engine is running, and it provides power to your air conditioner, power steering system, water pump and alternator (which is what charges your car's battery).

It's an important part of your car, and it's also a component that wears out over time. It's made out of synthetic rubber, which eventually breaks down from heat and friction. The serpentine belt needs to be inspected and replaced periodically. If you don't it will wear down until it reaches the point where it snaps under tension. Read on to learn some signs that your serpentine belt might need to be replaced, and to learn the consequences when you don't.

How Do You Know If Your Serpentine Belt Is About to Break?

When something is wrong with your serpentine belt, it'll start making squealing or chirping noises. You'll be able to hear these noises easily from the inside of your car.

Of course, several of the components under the hood of your car can start to make noise when they're about to fail. You can sometimes narrow it down to the serpentine belt by turning your steering wheel all the way to the right or to the left while the car is running.

Turning the steering wheel all the way in one direction puts some stress on your power steering system, which your serpentine belt is connected to. Once you've turned the wheel, you'll likely hear it start squealing again.

You can also visually inspect the serpentine belt. Unlike the timing belt, it's easy to see. It's the long belt connected to the engine that snakes through multiple pulleys. If it has cracks in it or if it seems like some of the synthetic rubber has crumbled away, have it replaced.

What Happens When Your Serpentine Belt Breaks?

The first thing that happens is physical damage. The serpentine belt moves through its system of pulleys very quickly, and it's also under tension. Once it snaps, all of that force has to go somewhere. Snapped serpentine belts frequently fly off and damage other components under your hood, such as the radiator.

Second, everything it's connected to will no longer function. In most cars, this is the water pump, alternator, air conditioner and power steering system. Some cars have electric water pumps or power steering systems that are controlled electrically rather than attached to the serpentine belt, however.

Can You Drive With a Broken Serpentine Belt?

Technically, your engine will still run. Without the water pump, however, it will quickly overheat. If your serpentine belt breaks, you should immediately pull over to a safe area and stop your car. Having your car towed to an auto repair shop to have the serpentine belt replaced is much less expensive than replacing an engine that was destroyed by overheating.

If your water pump is controlled electrically, it's still not a good idea to drive. With no alternator, your battery won't recharge while you're driving. You run the risk of draining all of its charge while you're on the road, which will end up with your car breaking down.

That's why it's important to have your serpentine belt inspected and replaced according to the schedule in your car's service manual. You don't want to run the risk of damaging your car by driving with a serpentine belt that's about to break. If you think yours is failing or if it's time for an inspection, take your car to an auto repair shop and talk to a mechanic. Replacing a serpentine belt is inexpensive, and it's a quick job for a skilled mechanic.