System Diagram
CONTROL SYSTEM
The control system consists of input sensors, switches, the A/C auto amp. (microcomputer) and outputs. The relationship of these components is as shown in the figure below:
System Description
CONTROL OPERATION
Display
The operation status of the HVAC system is displayed on the screen.
A/C and AV Switch Assembly
MODE SWITCH
The air discharge outlets are controlled with this switch.
TEMPERATURE CONTROL DIAL (Driver Side)
The set temperature is increased or decreased with this dial.
TEMPERATURE CONTROL DIAL (Passenger Side)
AUTO SWITCH
DEFROSTER ( ) SWITCH
Mode doors are set to the defrost position with this switch. Also, intake doors are set to the outside air position, and compressor turns ON.
A/C SWITCH
Compressor turns ON or OFF with this switch.
(Pressing the A/C switch when the A/C switch is ON turns OFF the A/C switch and compressor.)
FAN CONTROL DIAL
The fan speed is manually controlled with this dial. Seven speeds are available for manual control (as shown on the display screen).
ON - OFF SWITCH
Compressor and blower turn OFF, intake doors and the mode doors are automatically controlled.
REAR WINDOW DEFOGGER SWITCH
When indicator is ON, rear window is defogged.
RECIRCULATION ( ) SWITCH
FRESH AIR ( ) SWITCH
DUAL MODE SWITCH
Air Conditioner LAN Control System
The LAN (Local Area Network) system consists of the A/C auto amp., the mode door motor, the air mix door motors and the intake door motor.
A configuration of these components is as shown in the figure below.
SYSTEM CONSTRUCTION
A small network exists between the A/C auto amp., the mode door motor, the air mix door motors and the intake door motor. The A/C auto amp. and motors are connected by data transmission lines and motor power supply lines. The LAN network is built through the ground circuits of each door motor.
Addresses, motor opening angle signals, motor stop signals and error checking messages are all transmitted through the data transmission lines connecting the A/C auto amp. and each door motor.
The following functions are contained in LCUs built into the mode door motor, the air mix door motors and the intake door motor.
Operation
The A/C auto amp. receives data from each of the sensors. The A/C auto amp. sends mode door, the air mix door and the intake door opening angle data to the mode door motor LCU, the air mix door motor LCUs and the intake door motor LCU.
The mode door motor, the air mix door motors and the intake door motor read their respective signals according to the address signal. Opening angle indication signals received from the A/C auto amp. and each of the motor position sensors is compared by the LCUs in each door motor with the existing decision and opening angles. Next, HOT/COLD, DEF/VENT or FRE/REC operation is selected. The new selection data is returned to the A/C auto amp.
Transmission Data and Transmission Order
A/C auto amp. data is transmitted consecutively to each of the door motors following the form as shown in the figure below.
START:
ADDRESS:
OPENING ANGLE:
ERROR CHECK:
STOP SIGNAL:
AIR MIX DOOR CONTROL (AUTOMATIC TEMPERATURE CONTROL)
FAN SPEED CONTROL
With pressing AUTO switch, the blower motor starts to gradually increase airflow volume.
When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flowing.
INTAKE DOOR CONTROL
MODE DOOR CONTROL
MAGNET CLUTCH CONTROL
When A/C switch, AUTO switch or DEF ( ) switch is pressed, A/C auto amp. transmits compressor ON signal to ECM, via CAN communication.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant pressure sensor signal, throttle angle, etc.). If it judges compressor can be turned ON, it sends compressor ON signal to IPDM E/R, via CAN communication.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate compressor.
When sending compressor ON signal to IPDM E/R via CAN communication line, ECM simultaneously sends compressor feedback signal to A/C auto amp. via CAN communication line.
Steering switch
Description
When one of the steering wheel audio control switches is pushed, the
resistance in the steering wheel audio
control switch circuit changes, depending on which button is pushed.
Diagnosis Procedure
1.CHECK STEERING SWITCH RESISTANCE
Disconnect steering switch connector M88. ...
P0102, P0103 MAF sensor
Description
The mass air flow sensor (1) is placed in the stream of intake air. It
measures the intake flow rate by measuring a part of the entire
intake flow. The mass air flow sensor controls the temperature of the
hot wire to a certain amount. The heat generated by the hot wire is
re ...
Air conditioner system refrigerant and oil recommendations
The air conditioner system in your NISSAN
vehicle must be charged with the refrigerant
HFC-134a (R-134a) and Genuine
NISSAN A/C System Oil Type ND-OIL8 or
the exact equivalents.
CAUTION
The use of any other refrigerant or oil may
cause severe damage to the air conditioning
system and may req ...