Ram Trucks 2015 Chassis Cab Commercial - Owner Manual - Manual (Page 306)

Window Fogging and Frosting
Vehicle windows tend to fog on the inside of the glass in
mild, rainy and/or humid weather. Windows may frost
on the inside of the glass in very cold weather. To clear
the windows, select Defrost or Mix mode and increase
the front blower speed. Do not use the Recirculation
mode without A/C for long periods, as fogging may
occur.
NOTE:
Automatic Temperature Controls (ATC) will au-
tomatically adjust the climate control settings to reduce
or eliminate window fogging on the front windshield.
When this occurs, recirculation will be unavailable.
Outside Air Intake
Make sure the air intake, located directly in front of the
windshield, is free of obstructions such as leaves. Leaves
collected in the air intake may reduce airflow, can cause
odor, and if they enter the plenum they could plug the
water drains. In winter months, ensure the air intake is
clear of ice, slush and snow.
304 UNDERSTANDING YOUR INSTRUMENT PANEL