During the winter, you would depend highly on your car’s window defogger to help you pull through the fog and frost hindering your rear view. Therefore, you must be well-versed with your car’s window defogger to effectively use it.
Rear Window Heater:
The rear glass defogger is a built-in heater that is a part of your rear windscreen. This heater is meticulously crafted to prevent your car’s rear window from being affected by fog, condensation or frost. By using the thin metal strips embedded in the car’s glass, the heater operates by generating and passing heat through the metal strips, effectively removing moisture build-up on the windscreen and improving visibility.
Window Heater Functionality:
There are two common systems used by manufacturers to activate the car’s window heating, timer-based and sensor-based systems.
- Timer-based system: In this system, you need to manually activate the rear heater from the dashboard by pressing a button or switch. Once activated, it runs typically for around 10 to 15 minutes to prevent overheating and avoid draining the battery life of the car. After the designated time has passed, the timer-based rear window heater shuts off automatically. However, if your car requires additional defogging, you must reactivate it manually.
- Sensor-based system: This highly advanced system is more convenient as it utilizes a temperature sensor mounted on the rear windshield to monitor the glass temperature continuously. Therefore, the car’s heater in a sensor-based system doesn't run for a set time but gauges the temperature and automatically turns off when it is at an optimal level. Additionally, any fog reoccurrence is easily detected by the sensor and reactivates or repeats if needed to ensure clear visibility.
Window Defogger Tips:
- For optimal results, you should activate your car’s rear window defogger as soon as you notice any signs of fog or frost because it is easier to clear light condensation than heavy frost buildup.
- Allow the heater to directly reach your car’s windscreen by ensuring you clear any mist from the rear window before turning on the defogger.
- Frequently examine the condition of your rear wiper blades, and wipe off excess moisture if any.
- To enhance the defogging process, use the defogger simultaneously with your car's air conditioning system as the A/C helps remove moisture from the air.
- You must reactivate the defogger for more clearing time if you have a sensor-based auto-shutoff feature.
- Avoid scrapers or other harsh tools for frost removal, as they could damage your heater.
Uptime of a Rear Window Heater:
Typically, window heaters operate for about 10-15 minutes for every activation cycle to prevent overheating and protect your car's battery. However, newer models feature sensors that may continuously run until the glass reaches optimal visibility.
If the temperature drops or condensation reoccurs, the defogger will automatically restart. However, for older timer-based systems, you would need to repress the button to initiate another activation cycle if the fog persists even after 15 minutes.
Now that you are fully aware of the functionality and usage of the rear window defogger, you will be able to use it more effectively. Remind yourself to turn on your defogger at the very first sign of fog or frost as that would help you see better when driving and prevent your windscreen from fogging or frosting.
About the Author: Darren Pay and Justin Oakes are co-owners of A1 Windscreens, a car glass repair company that also specialize in ADAS calibration. The company also provides same-day services and fast glass services for locals to ensure they are up and back on the road in no time.
