Automatic blower fan control for cars

In case you were not aware of it, the rush-hour can affect your health. Stuck in a traffic jam or caught in the dense traffic in a big city, car drivers are often forced to switch off the fan to prevent being choked by the exhaust fumes produeed by the vehicle in front of them. Switching the fan on and off every minute or so to keep the fumes out is a nuisance, and calls for an automatie switch controlled by the engine speed. Such switches exist, but unfortunately for most of you they are only found in top-of-the-range cars equipped with an airconditioning system.