Also sometimes referred to as an electrochromic rearview mirror, the auto-dimming rearview mirror will dim the reflection from the headlights of other vehicles on the road at night. Electrochromic materials change colours they are charged with an electrical current. For example, it will darken if you were to send a volt throughout and brighten up again once the voltage is removed. This is a chemical reaction that is jumpstarted by electricity. Applying this technology to a rearview mirror causes the surface of the mirror to darken when a light source hits it. In other words, it changes the way the glass reflects light. This type of mirror also typically has cameras and photodiode-based photodetectors (sensors) that are sensitive to light. Known as semiconductors, they can transform light into a current. Attached to a microprocessor that detects headlight glare, the current (or volt) is sent through the electrochromic material - which then responds by darkening. The mirror is comprised of two glass layers with gel in between. This is the space in which the electrochromic material resides. It is what darkens when harsh light hits it. Please keep in mind that some models may also come with a camera display. Contact Ford Parts BC to order a replacement now!