Peterbilt Model 320 Operator's Manual after 8-07 - Peterbilt Motors ...

Heater
controller for that axle to go into the fail-safe mode, and the
warning light will give a shutdown signal. In this case, the
anti-lock system can be turned back on, and the warning
light extinguished, by turning the key switch OFF and ON,
after the vehicle has been brought to a full stop. When the
key switch is turned back on, the warning light will illuminate
and remain on for 3 to 5 seconds. This is a built-in function
test of the warning light.
Cab Heater-Air Conditioner
The combination heater-air conditioner provides comfort
for those in the cab through accurate control of the cab environment
in all weather conditions. Regular attention will
help you keep your unit running well.
NOTE: Keep the engine exhaust system and the
vehicle’s cab ventilation system properly maintained.
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
PART 8: MAINTENANCE AND SERVICE
• whenever the exhaust system, underbody, or
cab is damaged
• Allow for the proper operation 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.
• Keep the exhaust pipe area clear to help reduce
the buildup of exhaust gases under the vehicle.
Perform the following checks every 3 months or 30,000
miles / 48,000 km, whichever occurs first:
Heater
• Check all heater controls for full-range operation.
• Check hoses, connections, and heater core for condition
and leaks.
• Check the drain pan of the fresh air vent for trapped
water before assuming that there is a leak in the heating
system.
• If the heater core is leaking, take the vehicle to a Peterbilt
dealer for proper heater service or repair.
• Check the heater core for debris blocking the air flow. If
the blower is functioning properly, yet the heater is not
– 184 – Y53-6015 R(08/07)