How the Defroster Works

News & Information

By Allen (Advisor Team)

A car defroster is a component that can be found commonly on modern vehicles. Normally, defrosters on the vehicle’s front side will use their current, while the rear defrosters use electric power.

A working defroster’s main functionality ensures the driver maintains good visibility and avoids fogging on the front and rear windows. This component is important, especially in humid weather or cold winter days. You need to ensure that your vehicle defroster is working properly, especially if there’s a threat of frost or ice building up on the windshield during the winter. Older vehicles usually have defrosters located on the front windshield. Meanwhile, rear defrosters are also used on newer vehicles so drivers can see the car’s backside much better.

There are differences in the components used to control and activate the front and rear defrosters. The specifications will depend on the brand, model, and year of the vehicle that you’re driving. This post will try to outline the defroster systems so you can find out about the functionality of this component.

How The Defroster Works

What is the Function of a Window Defroster?

Two types of window defrosters are usually used on vehicles nowadays, the front defrosters for windshield and rear defrosters for rear windows. The main objective of using a defroster further insult is to dissipate the condensation that might build up from the difference in temperature from both sides of the windshield. When the outside weather is colder than the inside temperature, droplets of water form on the windows. Temperature difference inside and outside your vehicle causes window condensation. If the temperature is freezing, there’s also a possibility of the condensation turning into frost or ice. You will need to use defrosters to thaw and remove the frozen water.

The Working Mechanism of Front and Rear Window Defrosters

The simplest difference between front and rear defrosters is that front defrosters work by using air circulation, while the real defroster usually uses electrical power. You can usually notice vents installed on the front defroster to face the windshield. The vehicle will use the fan and blower motor to circulate air from the air conditioning unit and the heating component.

While different vehicles will employ different processes to activate the front defrosters, you can generally turn the front defroster by opening the vents and turning on the defroster fan with the correct setting. You can also set the temperature of the defroster. If the weather is cold, the front defrosters might take a few minutes to create heat that will eliminate condensation on the windows.

As mentioned, rear defrosters usually use electrical power. You can usually notice thin lines running on the rear window of your vehicle. These electrical fibers can activate the defrosting mechanism due to their embedded position. Your vehicle will have a special button that you can use to turn on the rear defrosters.

How to Activate the Defrosters

Front defrosters use hot temperatures from the blown air to dissipate condensation. But the heating component will need a few minutes to build up heat from the heater core. This process will also open the thermostat if the coolant has reached a suitable temperature. The heater core will receive hot water, activating the blower fan to push warm air through the front defroster’s vents. Condensation or frozen water will dissipate with the heat warming up the windows. Therefore, the heater is important to ensure that the front defrosters can function properly.

Electric power is used for the mechanism on the rear window defrosters. You will be able to see electrical lines running on the rear window. When you activate the rear defroster, the electrical power will create heat on the lines, removing the frozen water quickly. The mechanism from electrical defrosters is usually fast and will work as soon as you turn it on. Newer vehicles also have electrical defrosters embedded along the windshield’s edges. This is to enhance the defrosting system for the front windows.

This electrical defrosting system is also employed on heated side-view mirrors. The function ensures you can see your vehicle’s surrounding area while driving. But you will not be able to see obvious lines on the side windows. You should also know that the heaters will not produce enough heat to burn your skin when you touch the windows due to the low temperature of the component.

Common Problems with Defrosters

Problems on defrosters are usually hard to notice, and you will not know about them until the component has complete failure. There are many reasons why the situation can happen, including:

  • You need to replace the buttons or knobs since they have been broken or stopped working.
  • An overloaded circuit caused by a blown fuse can render your defroster unable to connect to the fuse, and you may need to get the component checked by professional mechanics.
  • Terminal edges are missing. This condition can occur when your windows are cracked, or the tint has come off.
  • The antifreeze level is too low. This condition will prevent the heater core from producing enough heat for the defroster.
  • Damaged wires. Connections to the defrosters are disturbed by the wires that have been frayed or broken.
  • Clogged vents. Defroster vents can get clocked by debris and other deposits, making them unable to blow hot air to the windshield.

It is always advisable to get help from a professional mechanic if your defrosters are not working as they should. This will make it possible for them to find the real cause of the defroster’s problems and find quick and proper solutions for it.