Auto-dimming IRVM stands for "auto-dimming interior rear-view mirror". It is a feature found in some vehicles that automatically dims the rear-view mirror to reduce the amount of glare that enters the driver's eyes from the headlights of vehicles behind them.

The auto-dimming function is typically accomplished through the use of electrochromic glass, which changes its level of tint in response to an electrical charge. The rear-view mirror contains a sensor that detects the amount of light entering the vehicle from behind, and when the sensor detects an excessive amount of glare, it sends an electrical charge to the electrochromic glass, causing it to darken and reduce the amount of glare reflected in the mirror.

Overall, an auto-dimming IRVM can help improve visibility and reduce driver fatigue, especially during night driving, by reducing the distraction and discomfort caused by the glare of headlights from other vehicles