The base heater system is designed to provide heating, ventilation, windshield defrosting, side window defogging, and on some vehicles, heating directly to the rear seat area.
The heater and fan assembly blower regulates the airflow from the air inlet for further processing and distribution.
The heater core transfers the heat from the engine coolant to the inlet air.
The temperature door regulates the amount of the air that passes through the heater core. The temperature door also controls the temperature of the air by controlling the mix of the heated air and the ambient air.
The mode door regulates the flow and the distribution of the processed air to the heater ducts and to the defroster ducts.
The console mounted heating and ventilation control panel contains 3 rotary control knobs, and 2 push control knobs, which operate as follows:
The heater core heats the air before it enters the vehicle. Engine coolant is circulated through the core to heat the outside air passing over the fins of the core. The core is functional at all times and may be used to temper conditioned air in the A/C mode as well as in the heat or the vent mode.
This vehicle is equipped with rear seat heater ducts. Should there be no airflow to the rear, look for any obstructions, such as items on the floor under the front seats. Also inspect for air leaks between the heater/air distributor assembly and the rear ducts.
