The simple answer to what these lines are is that they are defrosters and, in fact, the lines themselves are actually small wires. Built right into the glass, these wire lines help to quickly defrost your back window to get it cleared up in minutes.
Why are there black dots on windshield?
Even more intriguingly, these dots also appear on the windshield right behind the rear-view mirror. In this position, they serve the purpose of shielding the sun that reflects from between the two front sun-visors, which can then hit your field of vision. This smattering of dots is known as the “third visor frit.”
What are defroster lines for?
The defroster grids are the skinny lines that run across your rear windshield, and their job is to remove any fog or melt any ice in the winter by generating heat to give your premier visibility. However, a damaged defroster grid can severely affect your visibility and put you in danger.
How do I know what kind of windshield I have?
Regardless of the windshield type, one of the easiest ways to figure out which windshield you have is to place a piece of white or yellow paper and tape it behind the writing on the bottom of the windshield from the inside of the car. Take a picture with your phone and text or email it to the auto glass shop.
What are defroster lines made of?
These conductors may be composed of a silver-ceramic material printed and baked onto the interior surface of the glass, or may be a series of very fine wires embedded within the glass. The surface-printed variety is prone to damage by abrasion, but can be repaired easily with a conductive paint material.