System Components - Control: Controller

The operation of the A/C system is controlled by the switches on the control head. This console-mounted heating and ventilation panel contains the following:

Three Rotary Control Knobs

• The Rotary Temperature Control Knob
  • Actuates by cable
  • Varies the mix of the fresh air from outside the vehicle with the heated air from inside the vehicle to suit individual preference
  • Raises the temperature of the air entering the vehicle by rotation toward the right, or the red portion of the knob
• The Rotary Mode Control Knob
  • Actuates by vacuum
  • Regulates the air distribution between the windshield, the instrument panel, and the floor vents
• The Rotary Blower Control Knob
  • Turns on to operate the blower motor at 4 speeds
  • Turns OFF to stop the blower
  • Operates completely independently from both the mode control knob, that regulates the defroster door, and the temperature control knob
  • Changes the fan speed in any mode and at any temperature setting-However, if the rotary blower control knob is OFF, the A/C system is OFF, regardless of the position of the A/C push knob

Three Push Knobs

• The A/C Push Knob
  • Controls the A/C
  • Turns the A/C on when the push knob is pressed and the indicator lamp is illuminated-The rotary blower control knob must be in 1 of its 4 positions for the A/C to function.
• The Rear Window Defogger Push Knob
  • Controls the rear window defogger
  • Turns on the rear window defogger when the push knob is pressed and the indicator lamp is illuminated
• The Fresh Air Control Push Knob
  • Switches between recirculating passenger compartment air or bringing outside air into the passenger compartment
  • Defaults to fresh air mode-The indicator lamp is illuminated when recirculation is selected.
  • Operates the inlet air door by vacuum

The electric engine cooling fans are operational any time the A/C control is on. This added feature is part of the A/C controller function and is aimed at preventing excessive compressor head temperatures. It also allows the A/C system to function more efficiently. The operation of the cooling fans is controlled by the ECM through the cooling fan relays.