HVAC Control Systems: Heaters: Description

NOTE: Wiring diagrams are at end of article.

System is an air-mix type in which outside air is heated and then mixed in varying amounts with cooler outside air to attain desired temperature System consists basically of three parts: Blower and air inlet assembly, heater air distributor assembly, and heater control assembly.

Heating components are attached to dash panel on right side of vehicle. Blower and air inlet assembly and water hoses ore located on the engine side of dash panel while heater core and distributor duct are on passenger side. System has no water valve, therefore water circulation keeps heater core hot at all times. Air passing through core receives maximum heat.

Operation of blower motor is controlled by the fan switch. The motor is connected in series with the fan switch and blower resistor assembly. A 25 amp fuse is provided to protect blower circuit operation.