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.
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% ethylene256 UNDERSTANDING YOUR INSTRUMENT PANEL
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.
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.
4 UNDERSTANDING YOUR INSTRUMENT PANEL 257
Inflation pressures specified on the placard are always
“cold tire inflation pressure.” Cold tire inflation pressure
is defined as the tire pressure after the vehicle has not
been driven for at least three hours, or driven less than
1 mile (1.6 km) after a three hour period. The cold tire
inflation pressure must not exceed the maximum infla-
tion pressure molded into the tire sidewall.
Check tire pressures more often if subject to a wide range
of outdoor temperatures, as tire pressures vary with
temperature changes.
Tire pressures change by approximately 1 psi (7 kPa) per
12°F (7°C) of air temperature change. Keep this in mind
when checking tire pressure inside a garage, especially in
the winter.
Example: If garage temperature = 68°F (20°C) and the
outside temperature = 32°F (0°C) then the cold tire inflation pressure should be increased by 3 psi (21 kPa),
which equals 1 psi (7 kPa) for every 12°F (7°C) for this
outside temperature condition.
Tire pressure may increase from 2 to 6 psi (13 to 40 kPa)
during operation. DO NOT reduce this normal pressure
build up or your tire pressure will be too low.
Tire Inflation Pressure – 4500/5500 with Steel
Carcass Ply Tires
This type of tire utilizes steel cords in the sidewall. As
such, they cannot be treated like normal light truck tires.
Adjusting tire pressure must be performed by personnel
trained, supervised and equipped accordingly.
Inflation Pressure Adjustment When Mounted to
Vehicle
During procedures when adding tire inflation pressure,
the technician or individual must utilize a remote infla-
tion device, and ensure that all persons are clear of the
trajectory area.306 STARTING AND OPERATING
Radial Ply Tires
WARNING!Combining radial ply tires with other types of tires
on your vehicle will cause your vehicle to handle
poorly. The instability could cause an accident result-
ing in serious injury or death. Always use radial ply
tires in sets of four (or six, in case of trucks with dual
rear wheels). Never combine them with other types
of tires.
Cuts and punctures in radial tires are repairable only in
the tread area because of sidewall flexing. Consult your
authorized tire dealer for radial tire repairs. Tire Spinning
When stuck in mud, sand, snow, or ice conditions, do not
spin your vehicle’s wheels faster than 30 mph (48 km/h)
or for longer than 30 seconds continuously without
stopping when you are stuck.
Refer to “Freeing A Stuck Vehicle” in “What To Do In
Emergencies” for further information.
WARNING!Fast spinning tires can be dangerous. Forces gener-
ated by excessive wheel speeds may cause tire dam-
age or failure. A tire could explode and injure some-
one. Do not spin your vehicle’s wheels faster than
30 mph (48 km/h) or for more than 30 seconds
continuously when you are stuck, and don’t let
anyone near a spinning wheel, no matter what the
speed.
5 STARTING AND OPERATING 309
allowed in the United States. MMT is prohibited in
Federal and California reformulated gasoline.
Materials Added To Fuel
All gasolines sold in the United States are required to
contain effective detergent additives. Use of additional
detergents or other additives is not needed under normal
conditions and would result in unnecessary cost. There-
fore, you should not have to add anything to the fuel.
Fuel System Cautions
CAUTION!Follow these guidelines to maintain your vehicle’s
performance:
• The use of leaded gas is prohibited by Federal law.
Using leaded gasoline can impair engine perfor-
mance, damage the emission control system.
(Continued) CAUTION! (Continued)• An out-of-tune engine, or certain fuel or ignition
malfunctions, can cause the catalytic converter to
overheat. If you notice a pungent burning odor or
some light smoke, your engine may be out of tune
or malfunctioning and may require immediate
service. Contact your authorized dealer for service
assistance.
• When pulling a heavy load or driving a fully-
loaded vehicle when the humidity is low and the
temperature is high, use a premium unleaded fuel
to help prevent spark knock. If spark knock per-
sists, lighten the load, or engine piston damage
may result.
(Continued)320 STARTING AND OPERATING
WARNING! (Continued)• Guard against carbon monoxide with proper
maintenance. Have the exhaust system inspected
every time the vehicle is raised. Have any abnor-
mal conditions repaired promptly. Until repaired,
drive with all side windows fully open.
ADDING FUEL
The fuel tank filler tube has a restricting door about 2 in
(50 mm) inside the opening. If using a portable fuel
container, it should have a flexible nozzle long enough to
force open the restricting door. CAUTION!• Damage to the fuel system or emissions control
system could result from using an improper fuel
tank filler tube cap (gas cap). A poorly fitting cap
could let impurities into the fuel system. Also, a
poorly-fitted aftermarket cap can cause the MIL
(Malfunction Indicator Light) to illuminate due to
fuel vapors escaping from the system.
• A poorly fitting gas cap may cause the MIL to turn
on.
• To avoid fuel spillage and overfilling, do not “top
off” the fuel tank after filling.
NOTE: When the fuel nozzle “clicks” or shuts off the
fuel tank is full.322 STARTING AND OPERATING