OPERATING THE AIR CONDITIONER METHOD OF OPERATION SELECTING AIR VENT OPERATION OF CONTROL PANEL The effectiveness of the air con- ditioning system can be increased by selecting the most suitable vent. Do not turn the fan switch on when all the vents are closed. * If the outside air is extremely dusty, set the fan switch to the H position. This will pressurize the cab and prevent the dust from entering. - 44 - W-00058-A