What are the lines on the rear window?
3 Answers
The horizontal lines on the rear window glass of a car are called defrosters, also known as demisters. Function of the car demister switch: Adjust the car demister to reduce moisture, fog, and frost on the surface of the front and rear windshields and the exterior rearview mirrors, thereby improving visibility. The symbol for the car demister switch is the front windshield with three upward-curving lines. A semicircular symbol represents the front windshield, while a rectangular symbol indicates the rear windshield. Demister button symbol: The interior demister button is located near the air conditioning control panel, and the icon on this button is easily recognizable. The icon on this button is a fan shape with many curves, representing demisting.
Having driven in the north for many years, the lines on the rear window are actually heating resistor wires embedded in the glass, used for defogging and defrosting. Especially on cold mornings when ice forms, pressing a button melts it, which is crucial for maintaining clear rear visibility. I remember one winter on the highway when fog suddenly reduced visibility, nearly causing an accident—thankfully, the system kicked in just in time, allowing me to stop safely. In daily use, avoid scratching with hard objects like keys or metal scrapers to prevent breaking the wires, as repairing them requires replacing the entire glass, costing around 1,000 to 2,000 RMB, but it’s worth it. Additionally, in modern car models, these lines may also integrate antenna functions or serve as decorative elements to enhance aesthetics. Regularly check if all the wires are functioning by shining a flashlight to spot any breaks—otherwise, it could pose a significant safety risk.
As someone who frequently repairs cars, let me tell you that those lines on the rear windshield are defroster heating elements. They quickly heat the glass surface with electric current to melt frost and fog, ensuring rearview safety. Common issues include broken lines due to scraping or localized failure caused by chemical cleaner corrosion, which must be addressed promptly. Otherwise, driving in rainy conditions becomes dangerously like driving blindfolded. Preventive measures include cleaning with a soft cloth and warm water, minimizing the use of strong solvents, and parking in a garage during winter to reduce frost buildup, which can extend their lifespan. Repair costs aren't high, but replacing the glass is time-consuming. From practical experience, I've learned that maintaining good driving habits saves both hassle and money.
