Front - Automatic Temperature Control (ATC)

AUTOMATIC TEMPERATURE CONTROL (ATC)

The A/C-heater control (1) for the automatic temperature control (ATC) single zone front heating-A/C system allows the front seat passengers the ability to automatically or manually regulate air temperature as well as fan speed. All controls are identified by ISO graphic symbols.





The front A/C-heater control and integral computer (1) is located in the instrument panel and contains:

- a rotary control that selects comfort temperatures from 15° to 29° C (60° to 85° F) (2).
- a push button for manually increasing fan speed (3).
- a push button air recirculation control (4). An indicator lamp illuminates when the button is pressed, or when the system exceeds 80 percent circulated air under automatic control due to high A/C demand.
- a rotary control for manually selecting output modes or automatic operation (5).
- an infrared sensor that detects thermal radiation emitted by the front seat occupants and their surroundings (6).
- a push button rear window defogger on/off control (7). An indicator lamp illuminates when the rear window defogger system (EBL) is in operation. The indicator lamp illuminates even with the heating-A/C system turned off.
- a spring loaded note paper holder (8).
- a push button for A/C on/off control and residual engine heat utilization (REST) function (9). Indicator lamps illuminate when either the A/C system is in operation, whether under manual or automatic control and when the REST function is selected.
- indicator lamps which illuminate to reflect selected fan speeds and defroster mode operation (10).
- a push button for manually decreasing fan speed and turning the system completely turned off (11) (except for the rear window defogger system (EBL), if EBL is on).
- computer logic that remembers the settings of the controls when the ignition is turned off and retains those settings after a restart. If the system is off when the ignition is turned off it will be off when the engine is restarted, etc.
- computer logic that provides variable air recirculation under high temperature and humidity conditions. Because recirculation is generally accompanied by increased fan noise, the proportion of recirculated to outside air gradually approaches full recirculation over a broad temperature range.

The A/C-heater control for the ATC single zone front heating-A/C system is diagnosed using a scan tool Testing and Inspection.

The A/C-heater control cannot be repaired or adjusted and must be replaced if inoperative or damaged.