b. Heater/Defrost Controls. Figure 2-9 shows all heater controls on the center console.
Figure 2-9. Heater/Defrost Controls
1. Fan Switch. Four-position switch used to control operation and speed of heater
2. HEAT Control. Controls temperature of air that heats cab interior and defrosts
windshield. Temperature of air increases when control is pulled.
3. VENT Control. Controls flow of outside air to cab. When control is pulled, fresh
air is vented into cab.
4. DEFR (Defrost) Control. Controls windshield defrosting. Air is routed from heater
to defrost windshield when control is pulled.