Ram Trucks 2014 Chassis Cab Commercial - Owner Manual - Manual (Page 281)

Recirculation Control
When outside air contains smoke, odors, or
high humidity, or if rapid cooling is desired,
you may wish to recirculate interior air by
pressing the RECIRCULATION control button.
Recirculation mode should only be used temporarily. The
recirculation LED will illuminate on the soft and hard
keys when either button is selected. Push either soft or
hard key a second time to turn off the Recirculation mode
LED and allow outside air into the vehicle.
NOTE: In cold weather, use of Recirculation mode may
lead to excessive window fogging. The recirculation
feature may be unavailable (soft-key button greyed out)
if conditions exist that could create fogging on the inside
of the windshield. On systems with Manual Climate
Controls, the recirculation mode is not allowed in Defrost
mode to improve window clearing operation. Recircula-
tion will be disabled automatically if this mode is se-
lected. Attempting to use Recirculation while in this
mode will cause the LED in the control button to blink
and then turn off.
Summer Operation
The engine cooling system must be protected with a
high-quality antifreeze coolant to provide proper corro-
sion protection and to protect against engine overheating.
OAT coolant (conforming to MS-12106) is recommended.
Refer to “Maintenance Procedures” in “Maintaining Your
Vehicle” for proper coolant selection.
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UNDERSTANDING YOUR INSTRUMENT PANEL 279