OM3005.3 7/96 Operation - Section 3 Instrument Panel and Controls Page 3-25 HEATER/AIR CONDITIONER (FIGURE 3-7) (60) Fan The fan switch controls the heater/air condition three-speed blower mo- tor. The speeds are High, Medium, and Low. (61) Temperature Control Knob The push/pull knob controls the amount of hot water that will flow through the heater core to heat the air as it passes through the core and circulates throughout the cab. (62) Louvers The louvers can be rotated or adjusted to direct the flow of air to any part of the cab for the operator’s comfort. (63) Heater/Air Conditioner Switch The heater/air conditioner switch is a three-position toggle switch.
When the switch is moved to the "Heat" position, the blower motor is "On" and can be control- led by the three-position fan switch (55). If the switch is moved to the air conditioning position, the compres- sor magnetic clutch is turned "On" and the compressor will deliver R-12 refrigerant to the evaporator coil in the heater/air conditioner unit in the cab. FIGURE 3-7. HEATER/AIR CONDITIONER (64) Air Conditioning Temperature Control (65) Inside/Outside Air Control Knob The inside/outside air control knob is connected to a vent, which allows either outside or inside air to be circulated through the heater assembly.
The thermostatic switch controls the temperature of the air entering the truck cab. The control is set by the operator as desired. Pulling the knob out permits inside air to be recirculated through the heater. Pushing the knob all the way in permits outside air to be circulated through the heater assembly.