Navistar WorkStar Series, Operator'S Manual

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Controls/Features
Climate Control
WARNING
Never drive the vehicle unless the windshield and all other windows are clear. A fogged, ice/snow covered, or dirty windshield
or window limits vision, which could cause an accident, resulting in property damage, personal injury, or death. To improve
defroster efficiency, remove ice and/or snow by hand from the windshield and windows with a non-metallic scraper.
CAUTION
To clear system of humid air, operate blowers for 30 seconds at high speed, with the AIR FLOW/AIR CONDITIONER knob on the
normal heating position before selecting the DEF position. This will prevent fogging the glass, which can occur if humid air is
blown onto a cool windshield.
NOTE: The vehicle may be equipped with optional heater shut off valve(s) to prevent hot coolant from circulating through the heater core(s). Closing
the valve(s) during hot weather operation will improve A/C system performance. If the valves are shut off, in-cab temperature adjustment may become
limited. In addition, when shut off valves are closed, defrosters will only produce cold air.
Item No. Item Description
36 Fan Speed Control Use this control to regulate the amount of air provided to the vents in any mode you select. Turn
the knob clockwise to increase fan speed. Turning the control to the OFF position will shut OFF
the fan (and the A/C compressor if A/C is selected), but does not prevent outside air from entering
the vehicle. On vehicles equipped with A/C, moving the mode knob to the MAX A/C position, with
the fan ON, will close the fresh air door eliminating outside air from entering the vehicle.
37 Temperature Control Use this control to regulate the temperature of the air discharged from the vents. The blue area of
the control indicates cooler temperatures, while the red area indicates warmer temperatures.
38 Mode Control NOTE: The dot between the mode control icons is an additional mix position between the two
modes.
Use this control to direct the flow of air as follows:
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