SYSTEM DESCRIPTION
- The manual air conditioning system is controlled by a sequence of functions from the front air control, BCM, ECM, and IPDM E/R.
- The fan speed of the front blower motor is changed by the combination of the fan control dial (fan switch) operation and blower resistor control.
| Module/Function | Door control | A/C request signal | Compressor control | Cooling fan control |
|---|---|---|---|---|
| Front air control | DOOR CONTROL | SYSTEM DESCRIPTION | ||
| BCM | SYSTEM (With Intelligent Key) SYSTEM (Without Intelligent Key) | |||
| ECM | BCM, ECM, IPDM E/R | CAN COMMUNICATION | ||
| IPDM E/R | BCM, ECM, IPDM E/R | CAN COMMUNICATION |
PRINCIPLE OF OPERATION
Compressor is not activated.
Scheme 1
DESCRIPTION
- When A/C switch signal is received from front air control, the thermo control amp. transmits A/C ON signal to the BCM according to evaporator fin temperature.
- When the front blower motor is operated, the front air control transmits blower fan ON signal to the BCM.
- BCM transmits the A/C ON signal and blower fan ON signal to ECM via CAN communication line. Refer to " CAN COMMUNICATION SYSTEM: SYSTEM DESCRIPTION "
- ECM judges the conditions of each sensor (Refrigerant pressure sensor signal, accelerator position signal, etc.), and transmits the A/C compressor request signal to IPDM E/R via CAN communication line.
- By receiving the A/C compressor request signal from ECM, IPDM E/R turns the A/C relay to ON, and activates the compressor. Refer to " RELAY CONTROL SYSTEM: SYSTEM DESCRIPTION " (with Intelligent Key) or " RELAY CONTROL SYSTEM: SYSTEM DESCRIPTION " (without Intelligent Key)
CONTROL BY THERMO CONTROL AMP.
Low Temperature Protection Control
Scheme 2
- When thermo control amp. detects that evaporator fin temperature is 1.5°C (35°F) or less, thermo control amp. switches A/C ON signal to OFF and stops the compressor. When the evaporator fin temperature returns to 3°C (37°F) or more, the compressor is activated.
SWITCH OPERATION
| Fan control dial (fan switch) | Fan speed can be adjusted within a range from 1st to 4th. |
|---|---|
| MODE dial | Mode position is selected to an optimal position by operating this dial. |
| Intake lever | The air inlet changes REC <==> FRE each time by operation this lever. |
| Temperature control dial | The setting temperature can be selected to an optimum temperature by operating this dial. |
| A/C switch | The compressor control (switch indicator) is turned ON <==> OFF each time by pressing this switch while the blower motor is activated. |
- Each signal is sent to BCM by setting the D/F or DEF position.
- BCM judges the change of the air inlet and recognition of A/C switch ON or OFF according to input switch signal.
The front blower motor utilizes a brush-less motor with a rotating magnet. Quietness is improved over previous motors where the brush was the point of contact and the coil rotated.
When the blower speed dial is in one of the fan speed positions, the front air control outputs a fan ON signal to the BCM. When the A/C switch is pressed, the A/C switch LED illuminates and the front air control outputs a compressor ON signal to the BCM. Any mode control button can be selected. As long as the BCM receives a compressor ON signal and a fan ON signal from the front air control, the conditions required for the BCM to transmit a compressor ON request to the ECM have been met.
The BCM sends a compressor ON signal to ECM, via CAN communication line.
The ECM judges whether the compressor can be turned ON, based on each sensor status (refrigerant pressure sensor signal, throttle angle sensor, etc.). If it judges the compressor can be turned ON, it sends a compressor ON signal to IPDM E/R, via CAN communication line.
Upon receipt of a compressor ON signal from ECM, IPDM E/R turns the A/C relay ON to operate the compressor.
Symptom
- Insufficient cooling
- No cool air comes out. (Air flow volume is normal.)
Symptom
- Insufficient heating
- No warm air comes out. (Air flow volume is normal.)
See also:
• COMPONENT FUNCTION CHECK