RAM 2011 Ram Truck Chassis Cab, Owner'S Manual, Page: 268 / 494

Recirculation mode should only be used temporarily. The
recirculation LED will illuminate on the blower control
knob when this button is selected. Push the button 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
mode is not allowed in the Floor/Defrost Mix and
Defrost modes to improve window clearing operation.
Recirculation will be disabled automatically if these
modes are selected.
Summer Operation
The engine cooling system in air conditioned vehicles
must be protected with a high-quality antifreeze coolant
to provide proper corrosion protection and to protect
against engine overheating. A solution of 50% ethylene
glycol antifreeze coolant and 50% water is recommended.
Refer to “Maintenance Procedures” in “Maintaining Your
Vehicle” for proper coolant selection.
Winter Operation
To ensure the best possible heater and defroster perfor-
mance, make sure the engine cooling system is function-
ing properly and the proper amount, type, and concen-
tration of coolant is used. Refer to “Maintenance
Procedures” in “Maintaining Your Vehicle” for proper
coolant selection. Use of the air Recirculation mode
during Winter months is not recommended because it
may cause window fogging.
266 UNDERSTANDING YOUR INSTRUMENT PANEL