Temperature Regulation - Heating

TEMPERATURE REGULATION - HEATING







Discharge air temperature in the heating mode is controlled by the air blending flap. The rotary temperature knob controls the air blending flap, which determines how much air passes through the heater core.

Turning the knob clockwise will gradually increase the temperature of the air discharged into the cabin.

WATER VALVE







Water flow through the heater core is controlled by a water valve. The water valve is either open or closed. There is no pulsed regulation Of the valve. The water valve is open except when the temperature knob is in the full cold position. This is controlled by a microswitch mounted on the heater control panel.

The microswitch provides either switched:

- Ground in the 318ti or
- Power in the Z3


HEATER CORE







The single heater core unit has one coolant supply tube and one return tube. The heater core can be removed without removing the housing from the vehicle.

Remove the retaining screws as shown in the illustration. Drain the coolant from the system and disconnect the hoses from the supply and return tubes. Slide the heater core from the housing.