Why Won’t My Rear Defroster Work?

Rear Window Defroster | Lou's Car Care Center, Inc.

The defrosters in your car are a safety feature that helps to clear condensation and frost from your front and rear windshields. While both defrosters work to evaporate moisture from the windows, they do so in different ways.

Your front defroster works by directing hot air up through vents in the dashboard to defog the windshield from the inside. In some cars, the defrost controls will also activate the air conditioning and compressor. In warmer weather, cooling the air with A/C first can remove more moisture from the air to defog the windows better.


Rear Defroster | Lou's Car Care Center, Inc.


The rear defroster, in most cars, is electric. This system consists of rows of very thin heating elements on the inside of your rear window or hatch. These heating strips are connected to your vehicle’s electrical system and are controlled by a dashboard switch. The control switch typically runs on a timer that will automatically turn off the power after several minutes.


Rear Window Defroster Button | Lou's Car Care Center, Inc.


Causes of Rear Defroster Problems

  • Defroster Grid- One of the electrical lines that make up your rear defroster grid has broken.

  • Blown Fuse- The rear defroster system draws a lot of power and can blow a fuse.

  • Internal Wiring-  If the internal wiring that connects parts on the rear defroster system becomes disconnected or breaks, the electric current won’t reach the heating elements in the rear window.

  • Defroster Relay- A defective relay for the rear defroster system can block the flow of electricity.

  • Rear Defroster Switch- The dashboard switch that controls the rear defroster system can get stuck or stop working and may need to be replaced.

  • Damage from Aftermarket Tinting- Improper installation of aftermarket window tinting film applied to the rear window can cause problems with your rear defroster. Removing window tinting film from the rear window can take parts of the rear defroster gridlines, interrupting the entire system's electrical flow.
Fuse Box | Lou's Car Care Center. Inc.


Your defrosters are necessary for safe driving in rainy and winter conditions. Whether it’s your front or rear defroster, Lou’s Car Care is here for all of your electrical and air conditioning repairs. Serving the Baldwinsville, Syracuse, Camillus, Liverpool, North Syracuse, and Cicero, NY communities since 1976. Call us or schedule your appointment online today!



Let's Connect! Click on the links below to stay in touch with the Lou's Car Care Community:

Facebook Icon | Lou's Car Care Center, Inc.    Instagram Icon | Lou's Car Care Center, Inc.    Pinterest Icon | Lou's Car Care Center, Inc.    TikTok Icon | Lou's Car Care Center, Inc.    YouTube Icon | Lou's Car Care Center, Inc,    LinkedIn Icon | Lou's Car Care Center, Inc.
Lou's Car Care & Fleet Services is committed to ensuring effective communication and digital accessibility to all users. We are continually improving the user experience for everyone, and apply the relevant accessibility standards to achieve these goals. We welcome your feedback. Please call Lou's Car Care Center, Inc. (315) 638-0281 if you have any issues in accessing any area of our website.