How to Change the Set Temperature
The climate control unit has a function to change the set temperature +2.7 ºF (+1.5 ºC) or -2.7 ºF (-1.5 ºC) degrees.
NOTE: Verify that the climate control and A/C system is working properly before enabling the customize function to offset the set temperature.
The climate control unit displays the following during each change.
CLIMATE CONTROL SYSTEM DESCRIPTION - HUMIDITY/IN-CAR TEMPERATURE SENSOR
The humidity/in-car temperature sensor has a humidity sensor and an in-car temperature sensor. The climate control unit receives humidity information from the sensor to help control A/C compressor operation. When it is humid, the climate control unit operates the A/C compressor to prevent a windshield from being fogged. When the humidity is low enough, the climate control unit reduces the operating time for the A/C compressor. A flexible hose connects the sensor case to an aspirator on the HVAC box to improve the accuracy of temperature and humidity measurements.
NOTE: This illustration is an example only. Appearance and structure of the actual parts may vary depending on the model.
CLIMATE CONTROL SYSTEM DESCRIPTION - OVERVIEW
Climate Control
The climate control system transmits appropriate signals to each motor based on the information (sunlight, humidity, in-car temperature, outside air temperature) received from each sensor. See below for details.
The climate control unit optimizes these controls in order to maintain passenger comfort.
Relationship Between Vent (Air Outlet) Temperature and Actual In-Car Temperature
The climate control unit can automatically control vent temperature (air mix position), blower motor speed, blower intake (mode position), and A/C compressor operation to raise or lower the vehicle's interior temperature to match the customer's setting temperature. The actual vent outlet temperature largely depends upon the difference between the in-car temperature sensor reading and the customer's setting temperature.
Warm-Up Control
If heating is desired, and there is no available heat due to low engine coolant temperature, the climate control unit will slow the fan speed to avoid ventilating cold air. The climate control unit will gradually increase the fan speed as the engine coolant temperature rises.
The conditions that this control becomes effective are as follows:
Low Engine Coolant Temperature Control
When engine coolant temperature is low, the climate control system changes an air outlet position to the "DEF".
If engine coolant temperature gradually rises, the climate control system changes an air outlet position to the "HEAT/DEF". In addition, engine coolant temperature rises, to control the air outlet position by outlet air temperature.
Relationship Between Vehicle Speed and Blower Intake Mode
Because air resistance is different, the air volume is different in the "FRESH" mode and the "RECIRC" mode if the fan speed is constant. When a recirculation control damper is "FRESH", fresh air increases as vehicle speed rises. The climate control unit regulates fan speed to make the air volume of the "FRESH" mode the same as "RECIRC" mode.
A/C Control
To prevent the evaporator from freezing, the climate control unit switches the A/C compressor ON and OFF based on the evaporator temperature sensor value. While in the automatic operation mode, the climate control unit automatically switches the A/C compressor ON based on the evaporator temperature sensor value, as well as an ambient temperature and humidity.
MAX Control
When the temperature setting is adjusted to "MAX COOL (Lo)" or "MAX HOT (Hi)", the climate control unit overrides automatic control and defaults to the following operation:
CLIMATE CONTROL SYSTEM DESCRIPTION - SUNLIGHT SENSOR
The sunlight sensor is attached to the upper face of the instrument panel. The sunlight sensor uses a photodiode-type optical sensor which changes current in proportion to the sunlight intensity. The climate control unit reads the voltage fluctuation of the sunlight sensor.
NOTE: This illustration is an example only. Appearance and structure of the actual parts may vary depending on the model.