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Home >> Jaguar >> 2005 >> XK8 2D Convertible >> Repair and Diagnosis (Single Page) >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Control Components >> Control Components >> Control Components - Description & Operation >> Inputs / Outputs
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Inputs / Outputs

  1. Engine speed:
    • Input to the A/CCM from the ECM.
    • Heated windshield and backlight will be inhibited when engine speed < 50 RPM.
  2. Vehicle speed:
    • Input from the instrument cluster.
    • Blower speed control to minimize the effects of ram air. Road speed compensation is inhibited when maximum cooling LO, or maximum heating HI, is selected; also inhibited in defrost mode with airflow set to maximum.
    • Used to determine the frequency at which the exterior temperature display is updated.
  3. Coolant temperature (signal derived from ECM via instrument cluster):
    • Input from the heater matrix temperature sensor used to control water valve and thus vent temperatures.
    • Used to monitor the temperature of coolant at the heater matrix to assist the control of air outlet temperature.
    • Used to inhibit the blowers when heating is selected and the engine coolant temperature is below 30°C.
    • Is used to provide progressive increase in blower speed up to 60°C.
    • To inhibit the water valve and pump when the coolant temperature is = < 10°C
  4. Compressor ON signal: