The linear control with PWM (pulse-width modulation) is adopted to the blower motor speed control. Adopting it prevents the excess rotation of the blower motor and decreases the fuel consumption and noise.
The blower pulse controller changes the motor switching time using the pulse signal from A/C-ECU and the motor applied voltage equivalently to control the motor speed linearly.

In the heater unit, there are two layers of air; one which passes through the heater core, and another which does not pass through the core. One air mixing door is used for temperature control. The two-layer blow full mix heater with low ventilation resistance has increased air volume and has reduced noise.

When the defogger switch is turned to ON with the ignition switch ON, the manual air conditioner automatically turns off after approximately 11 minutes, and the automatic air conditioner turns off after 20 minutes to prevent the battery discharge.

If the air selection switch is in the outside air mode, information of the lighting switch position and the air thermo sensor sensing temperate is sent to A/C-ECU. Then, sending the signal form the engine-ECU to A/C-ECU executes the energy conservation control of the compressor when evaporator inlet air temperature is from approximately 10°C to approximately 30°C: evaporator outlet temperature is controlled higher than the freezing temperature. If lighting switch is turned ON (tail and headlamp), the temperature is controlled higher than OFF state, presuming of no sun shine.

If A/C-ECU detects that the refrigerant amount is less than the specified level or the refrigerant pressure is lower or higher than thresholds, the air temperature (using the air thermo sensor <for the manual air conditioner>, or outside air temperature sensor <for the automatic air conditioner> to measure the refrigerant gas expansion) and the refrigerant pressure (A/C pressure sensor) blink the A/C switch indicator lamp, and forcedly turns off the compressor to prevent the A/C system damage.

Depending on the A/C cooling load, the cooling fan speed is controlled continuously with PWM and the exterior noise in the intermediary stage is decreased. Also, the load of the alternator is decreased to improve the fuel economy.

If the outside air temperature is high with the A/C switch and the blower switch ON, A/C-ECU changes automatically from the outside air circulation state to the inside air circulation state to cool the room quickly. (With the inside air circulation state, the auto change control will not be made.) After that, only when the air conditioner switch or the blower switch is turned OFF, the change control is made. If the outside/inside air selection switch is operated after the auto change, the switch operation takes the priority.

If the inside air temperature is cooled quickly with the A/C switch and the blower switch ON, A/C-ECU set the inside air circulation mode automatically. Other than during cooling quickly, A/C-ECU gives priority to set the fresh air mode. If the outside/inside air selection switch is operated after the auto change, the switch operation takes the priority.