Understanding How Your Car Defroster Works

Follow This Guide When Using Your Car Defroster

The car defroster is one of the most misunderstood parts of a vehicle. It’s a simple device that performs an important service. Here’s what you need to know about your car defroster:

Kinds of Defrosters
In general, there are two kinds of defrosters. The most common one is located on the front of your vehicle. This uses the heat generated from your vehicle’s engine and from the HVAC system to direct air onto the window. The heat is pulled from the engine block while the cool air is treated by the HVAC. 

The other kind of defroster is most commonly found in the back window. If your vehicle has a rear defroster, there isn’t an engine block to send direct heat onto the window. Instead, it uses a thin wire that runs through the glass (if you look closely, you’ll see what looks like thin, parallel lines in the glass). This resistive heating defogs and de-ices the window. 

How Does the Car Defroster Work?
When you turn the defroster on, the vehicle will pull in air through the heater core (which takes heat off of the engine) and push it directly against the front windshield. The vents are located directly under the glass, which is why it defogs (or defrosts) from the bottom. It’s also why the defroster works better after the car has been running for a few minutes. This gives the engine some time to heat up. 

If you drive an electric vehicle, the process is a bit different. After all, there is no heat generated by an electric engine (the combustion engine inside a car burns fuel, which causes the heat). Instead, the entire vehicle will use resistance heating in most instances. However, this does use the vehicle’s battery power, so the charge does not last as long. 

Temperature Setting
In general, you want to use the opposite temperature setting than what is found outside. So, if it is cold, you want to set the defroster to hot, and if it is hot outside you want the temperature set at cold. This is because the fogging of your window is caused by moisture. The blowing air removes moisture from the window (it is also why your window is more likely to fog up in the winter, because your breath contains moisture and it clings to the glass). 

Get Your Car Defroster Checked at Valley Automall

If you’re having trouble with your car defroster, schedule maintenance at Valley Automall. Our service technicians will be able to identify and fix the issue or replace the defroster entirely. If you’re looking to upgrade your vehicle, contact us at 702-570-2257 to discuss your needs.