OM3212 08/11 Operator Cab and Controls - Section 32 Page 32-5 Air Conditioner Control Switch Air Conditioner control switch (5, Figure 32-3) is a three position switch that controls the air condi- tioner to cool the cab air. Moving the switch to the left activates the air conditioner. (The fan control must be switched ON for the air conditioner to function.) When the switch is in the center position, the air conditioner and the heater are both activated. When the switch is moved to the right side, only the heater is activated. Heater/air conditioner vents (6, Figure 32-3) may be rotated 360°.
There are three vents in the heater/air conditioner compartment (shown in Figure 32-3), four vents across the top of the panel, and one vent each in the RH and LH instrument panel pods. Air flow through the vents is controlled by manually opening, closing or turning the louvers. Heater/Air Conditioner Vents RETARDING CAPACITY CHART Retarding capacity chart (8, Figure 32-1 & shown below) provides the recommended maximum truck speeds for descending various grades with a fully loaded truck. The operator should reference the retarding capacity chart before descending any grade with a loaded truck.
Proper selection of road grade, truck speed, transmission gear range, and use of the retarder lever and/or brake pedal are required to maintain a safe speed. FIGURE 32-3. A/C & HEATER CONTROLS