Electrochromic Inside Rear View Mirror
The electrochromic (EC) inside rear view mirror receives power, ground and a reverse signal on the three wires that connect to it. It uses two light sensors to sense glare.1. The forward facing sensor determines if the outside light levels are low enough for the mirror to operate.
2. The rearward facing sensor detects glare from lights behind the mirror. When glare is detected, it outputs a signal to the mirror to dim at the required level.
3. The mirror dims to the level as directed by the rearward facing sensor. When the glare is no longer detected, the mirror returns to normal.