Functions and Features

Functions and Features

Automatic air conditioning control unit
The control unit features a prominent control and display panel that clearly shows air conditioner operational settings (delivered air volume, air outlet location, inside/outside air circulation, and set temperature). Desired temperature can be set in -17 °C (1 °F) increments. The current setting appears on the digital display.

Automatic temperature control
Vehicle interior temperature is maintained at the set level. It is unaffected by changes in vehicle speed, outside air temperature, and number of passengers.

Maximum cooling and heating
Moving the switch to the 18 °C (65 °F) position provides maximum cooling. Moving the switch to the 32 °C (90 °F) position provides maximum heating.

Automatic air flow control
Air flow is automatically and precisely regulated in response to set temperature change and/or changes in heater unit mixing door aperture.

Automatic air outlet selection
Appropriate air outlets (VENT, BE-LEVEL, FOOT, or DEF) are selected in response to changes in outlet temperatures. The mode switch permits manual selection of the desired air outlet.

Air source (Fresh air intake from outside the vehicle or recirculation of the air inside the vehicle) selection
Automatic switching between outside air (FRESH), recirculated inside air (RECIRC), or a combination of the two (MIX) occurs in response to changes in outlet temperatures. The intake switch permits manual selection of the air source (FRESH or RECIRC). Mixing of the two sources is not possible during manual operation. When the defrost mode switch (DEF) is pressed, the system automatically switches to outside air intake.

Cooler start-up control
When the vehicle is parked in a hot area for an extended period of time, the evaporator becomes hot. When the cooler is turned on, hot air is blown into the vehicle until the evaporator cools down. The cooler start-up control prevents blower operation until the evaporator is able to provide cool air.

Heater start-up control
When the vehicle is parked in a cold area for an extended period of time, the heater core becomes cold. When the heater is turned on, cold air is blown into the vehicle until the heater core heats up. The heater start-up control prevents blower operation to the air outlets until the heater core is able to provide warm air. Air is delivered through the defrost outlets.

Solar radiation offset
The sun sensor uses a photodiode to precisely determine the amount of solar radiation affecting the vehicle. The cooler operates in response to this radiation to quickly correct the vehicle interior temperature.

Switch position memory
Current switch positions are stored in memory when the ignition switch is turned off. When the ignition switch is turned on again, the switches automatically return to the position they were in when the ignition switch was turned off. This simplifies the restarting procedure.

Self-diagnosis function
The self-diagnosis switches on the control panel permit easy system troubleshooting. Refer to Troubleshooting with Self-Diagnosis Function in this section.

Automatic Air Conditioner Block Diagram:

Control Panel Layout:

Air Control Functions:

Control Panel Switch Operation - Part 1:

Control Panel Switch Operation - Part 2:

Control Panel Switch Operation - Part 3:

Control Panel Switch Operation - Part 4:

Control Panel Switch Operation