What does this button do?

Cars.com reviews a lot of new cars, mostly with the same volume knobs, hood releases and temperature settings. But sometimes the reviewers get in a car and wonder, "What the heck does this do?" Here we chronicle their ongoing quest to decipher dashboard hieroglyphics. Have you ever found mystery controls on a car? Leave your comments below. —Joe Bruzek, Cars.com

February 22, 2013