The electric rearview mirror automatically controls the glare from the headlights of the car behind you in nighttime or low light driving conditions.
When the engine is running, the glare is automatically controlled by the sensor mounted in the rearview mirror. The sensor detects the light level around the vehicle, and automatically adjusts to control the headlight glare from vehicles behind you.
Whenever the shift lever is placed in R (Reverse), the mirror will automatically go to the brightest setting to improve the driver’s view behind the vehicle.

To operate the electric rearview mirror:
CAUTION
When cleaning the mirror, use a paper towel or similar material dampened with glass cleaner. Do not spray glass cleaner directly on the mirror as that may cause the liquid cleaner to enter the mirror housing and damage the rearview mirror.
Day/Night rearview mirror (if equipped)
Blue Link® center (if equipped)Hyundai Tucson (LM) 2010-2015 Owners Manual: Severe driving conditions
A - Repeatedly driving short distance of less than 5 miles (8 km) in normal temperature
or less than 10 miles (16 km) in freezing temperature
B - Extensive engine idling or low speed driving for long distances
C - Driving on rough, dusty, muddy, unpaved, graveled or salt-spread roads
D - Drivin ...
Hyundai Tucson (LM) 2010-2015 Owners Manual: Maintenance when trailer towing
Your vehicle will need service more often when you regularly pull a trailer.
Important items to pay particular attention to include engine oil, automatic
transaxle fluid, axle lubricant and cooling system fluid. Brake condition is another
important item to frequently check. If you’re traileri ...