Why Tahoe headlights fog up
Most headlights today are plastic with a thin protective coat from the factory. Two things wear that coat down, and Tahoe has plenty of both.
The first is UV light. At about 6,200 feet, there’s less air to filter the sun, so lenses get a stronger dose every day the car sits outside. Over time, the coat breaks down, turns hazy and then yellow, usually worst along the top of the lens.
The second is grit. Sand spread on winter roads gets kicked up by the car in front and sandblasts the front of your car. Add ice scrapers, snow brushes and quick wipes with a gritty glove, and the lens ends up covered in tiny pits and scratches that scatter light.
Clear lenses matter more in winter
Winter days are short, and a lot of driving happens in the dark, often in falling snow. Cloudy lenses let less light through and spread it in the wrong places. You see less of the road edge, and oncoming drivers can get more glare.
In a snowstorm, every bit of clean, focused light helps. Restored lenses won’t make up for driving too fast for the conditions, but they do help your headlights do their job.
The drive up the hill and back often happens after dark, too, when weekend visitors head home after a day on the snow. That’s a lot of dark, winding miles for dim, yellow lights.
Clear lenses also make a car look newer. On a well-kept SUV, yellow headlights are often the one thing that makes it look tired.