2012 RAM CHASSIS CAB Owners Manual

blower will engage immediately if the Defrost mode is
selected, or by adjusting the blower control knob and
setting the fan to any fixed speed.
Manual Operation
This system offers a full complement of manual override
features.
NOTE: Each of these features operate independently
from each other. If any one feature is controlled manually,
the temperature doors will continue to operate automati-
cally.
There are six fixed blower speeds. Use
this control to regulate the amount of
air forced through the system in any
mode you select. The blower speed
increases as you move the control
clockwise from the OFF position. The blower fan speed can be set to any fixed speed by
adjusting the blower control knob. The fan will now
operate at a fixed speed until additional speeds are
selected. This allows the front occupants to control the
volume of air circulated in the vehicle and cancel the
Auto mode.
The operator can also select the direction of the airflow
by selecting one of the following positions.
Panel Mode
Air comes from the outlets in the instrument panel.
Each of these outlets can be individually adjusted to
direct the flow of air. The air vanes of the center outlets
and outboard outlets can be rotated to regulate or shut off
the airflow from these outlets.
Bi-Level Mode
Air comes from the instrument panel outlets, floor
outlets and defrost outlets.Blower Control
4 UNDERSTANDING YOUR INSTRUMENT PANEL 263

NOTE: In many temperature positions, the BI-LEVEL
mode is designed to provide cooler air out of the panel
outlets and warmer air from the floor outlets.
Floor Mode
Air comes from the floor outlets. A slight amount of
air is directed through the defrost and side window
demister outlets.
Mix Mode
Air comes from the floor, defrost and side window
demist outlets. This mode works best in cold or
snowy conditions. It allows you to stay comfortable
while keeping the windshield clear.
Defrost Mode
Air comes from the windshield and side window
demist outlets. Use Defrost mode with maximum
blower and temperature settings for best windshield and
side window defrosting. NOTE: While operating in the other modes, the system
will not automatically sense the presence of fog, mist or
ice on the windshield. Defrost mode must be manually
selected to clear the windshield and side glass.
The Air Conditioning (A/C) button allows the
operator to manually activate or deactivate the air
conditioning system. When in A/C mode and the
ATC is set to a cool temperature, dehumidified air flows
through the air outlets. If Economy mode is desired, press
the A/C button to turn off the A/C mode in the ATC
display and deactivate the A/C system.
NOTE:
• If the system is in Mix, Bi-Level or Defrost Mode, the
A/C can be turned off, but the A/C system shall
remain active to prevent fogging of the windows.
• If fog or mist appears on the windshield or side glass,
select Defrost mode and increase blower speed.264 UNDERSTANDING YOUR INSTRUMENT PANEL

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 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.
4 UNDERSTANDING YOUR INSTRUMENT PANEL 265

Vacation/Storage
Any time you store your vehicle or keep it out of service
(i.e., vacation) for two weeks or more, run the air
conditioning system at idle for about five minutes in
fresh air with the blower setting in high. This will ensure
adequate system lubrication to minimize the possibility
of compressor damage when the system is started again.
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. 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 make sure the air intake
is clear of ice, slush and snow.266 UNDERSTANDING YOUR INSTRUMENT PANEL

Operating Tips
4 UNDERSTANDING YOUR INSTRUMENT PANEL 267

STARTING AND OPERATINGCONTENTS  Starting Procedures .................... 273
▫ Normal Starting ..................... 273
▫ Automatic Transmission ............... 273
▫ Extreme Cold Weather
(Below –20°F Or  29°C) ............... 274
▫ If Engine Fails To Start ................ 274
▫ After Starting ....................... 275
 Engine Block Heater — If Equipped ........ 275
 Automatic Transmission ................. 276
▫ Key Ignition Park Interlock ............. 278 ▫ Brake/Transmission Shift Interlock System . . 278
▫ Six–Speed Automatic Transmission
(5.7L Engine) — If Equipped ............ 278
 Four-Wheel Drive Operation — If Equipped . . 288
▫ Manually Shifted Transfer Case – If
Equipped .......................... 288
▫ Shifting Procedure – Manually Shifted
Transfer Case ....................... 290
▫ Transfer Case Position Indicator Light ...... 291
5

▫ Electronically Shifted Transfer Case
(Four-Position Switch) – If Equipped ....... 292
▫ Shifting Procedure ................... 296
 Limited-Slip Differential ................. 298
 Driving On Slippery Surfaces ............. 299
▫ Acceleration ........................ 299
▫ Traction ........................... 299
 Driving Through Water ................. 300
▫ Flowing/Rising Water ................. 300
▫ Shallow Standing Water ............... 300
 Power Steering ....................... 302
▫ Power Steering Fluid Check ............. 303
 Parking Brake ........................ 304  Brake System ........................ 306
▫ Four-Wheel Anti-Lock Brake System ....... 307
 Tire Safety Information ................. 309
▫ Tire Markings ....................... 309
▫ Tire Identification Number (TIN) ......... 312
▫ Tire Terminology And Definitions ......... 313
▫ Tire Loading And Tire Pressure .......... 314
 Tires — General Information ............. 318
▫ Tire Pressure ....................... 318
▫ Tire Inflation Pressures ................ 319
▫ Radial Ply Tires ..................... 324
▫ Spare Tire Matching Original Equipped Tire
And Wheel – If Equipped .............. 324270 STARTING AND OPERATING