Operating Instructions Heating and Air Conditioning
Medium Duty
(R10/06) Y53-6008 – 39 –
aware of a refrigerant leak on your vehicle, have your
system serviced immediately and observe the fol-
lowing precautions:
– Stay away from the hot engine until the exhaust
manifold has cooled.
– Do not permit any open flame in the area. Even a
match or a cigarette lighter may generate a haz-
ardous quantity of poisonous gas.
– Do not smoke in the area. Inhaling gaseous
refrigerant through a cigarette may cause violent
illness.
WARNING! Never idle your vehicle for prolonged
periods of time if you sense that exhaust fumes
are entering the cab. Investigate the cause of the
fumes and correct it as soon as possible. If the
vehicle must be driven under these conditions,
drive only with the windows slightly open. Fail-
ure to repair the source of the exhaust fumes
may lead to personal harm.
NOTE: Keep the engine exhaust system and the
vehicle’s cab ventilation system properly main-
tained. It is recommended that the vehicle’s
exhaust system and cab be inspected:
• By a competent technician every 15,000 miles.
• Whenever a change is noticed in the sound of the
exhaust system.
• Whenever the exhaust system, underbody, cab or
sleeper is damaged.
NOTE: To allow for proper operations of the vehicle
ventilation system, keep the inlet grille at the base
of the windshield clear of snow, ice, leaves, and
other obstructions at all times.
WARNING! Do not stay in the vehicle with the
engine running or idling for more than 10 min-
utes with the vehicle’s Heater and A/C ventila-
tion system in RECIRC or at LOW FAN SPEED.
Even with the ventilation system ON, running
the engine while parked or stopped for pro-
longed periods of time is not recommended.
Controls
The heater and air conditioning control unit is mounted in the
center dash console, below the radio. The standard control
unit has four controls to regulate air flow and temperature in
