Nissan Pathfinder. Manual — part 688

COMPONENT PARTS

HAC-13

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

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Air mix door motor (Driver side)

The air mix door controls the mix of hot or cold air that enters the ventilation system. It is con-
trolled by the A/C auto amp. based on the position of the temperature dial. The air mix door mo-
tor receives position commands from the A/C auto amp. and reports actual door position back
via an LCU (Local Control Unit) installed inside the motor. Commands and responses are sent
across the LIN (Local Interconnect Network) to each motor simultaneously, with each motor
having its own unique address, thereby only responding to requests sent to its specific address.
The LCU reads the door position from a Position Balanced Resistor (PBR), also part of the mo-
tor, and returns that information to the A/C auto amp. The LCU switches the polarity of the cir-
cuits connected to the DC motor to drive the motor forward or backward as requested by the
front air control. If the air mix door moves to a position less than 5% or more than 95% of its
expected or allowed positions, the A/C auto amp. will set a DTC.

Air mix door motor (Passenger side)

The air mix door controls the mix of hot or cold air that enters the ventilation system. It is con-
trolled by the A/C auto amp. based on the position of the temperature dial. The air mix door mo-
tor receives position commands from the A/C auto amp. and reports actual door position back
via an LCU (Local Control Unit) installed inside the motor. Commands and responses are sent
across the LIN (Local Interconnect Network) to each motor simultaneously, with each motor
having its own unique address, thereby only responding to requests sent to its specific address.
The LCU reads the door position from a Position Balanced Resistor (PBR), also part of the mo-
tor, and returns that information to the A/C auto amp. The LCU switches the polarity of the cir-
cuits connected to the DC motor to drive the motor forward or backward as requested by the
front air control. If the air mix door moves to a position less than 5% or more than 95% of its
expected or allowed positions, the A/C auto amp. will set a DTC.

Ambient sensor

The ambient sensor measures the temperature of the air surrounding the vehicle. The sensor
uses a thermistor which is sensitive to the change in temperature. The electrical resistance of
the thermistor decreases as temperature increases.

AV control unit

AV control unit transmits A/C and AV switch assembly operation signal to A/C auto amp. via
CAN communication line.

BCM

BCM transmits blower motor ON signal to the front and rear blower motor relays.

Display unit
(except base audio system)

The display unit indicates operation status of the front and rear automatic air conditioning sys-
tem.

ECM

The ECM sends a compressor ON request to the IPDM E/R based on the status of engine op-
eration and load as well as refrigerant pressure information. If all the conditions are met for A/
C operation, the ECM transmits the compressor ON request to the IPDM E/R. The ECM shares
the refrigerant pressure sensor signal, engine RPM, and engine coolant temperature with the
A/C auto amp. via CAN communication line.

Front blower motor

The front blower motor varies the speed at which the air flows through the ventilation system.

Front blower motor relay

The front blower motor relay controls the flow of current to fuse 17 and 27 in the Fuse Block (J/
B). The relay is connected directly to ground, and is controlled by the BCM.

Fuse block (J/B)

Located in the passenger compartment, behind the left lower IP, the Fuse Block (J/B) contains
the front blower motor relay and several fuses required for the air conditioner control system.

IPDM E/R

A/C relay is integrated in IPDM E/R. IPDM E/R operates A/C relay when A/C compressor re-
quest signal is received from ECM via CAN communication line.

Intake door motor

The intake door motor controls the position of the intake door. Fresh air is allowed to enter the
cabin in one position, and recirculated inside air is allowed to enter in the other position. At times
the A/C auto amp. may command partial fresh or recirculation based on evaporator or coolant
temperatures. The intake door motor receives position commands from the front air control and
reports actual door position back via an LCU (Local Control Unit) installed inside the motor.
Commands and responses are sent across the LIN (Local Interconnect Network) to each motor
simultaneously, with each motor having its own unique address, thereby only responding to re-
quests sent to its specific address. The LCU reads the door position from a Position Balanced
Resistor (PBR), also part of the motor, and returns that information to the front air control. The
LCU switches the polarity of the circuits connected to the DC motor to drive the motor forward
or backward as requested by the front air control. If the recirculation door moves to a position
less than 5% or more than 95% of its expected or allowed positions, the front air control will set
a DTC.

Intake sensor

Intake sensor measures temperature of front evaporator fin temperature. The sensor uses a
thermistor which is sensitive to the change in temperature. The electrical resistance of the ther-
mistor decreases as temperature increases.

Component

Description

HAC-14

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

COMPONENT PARTS

REAR AUTOMATIC AIR CONDITIONING SYSTEM

In-vehicle sensor

In-vehicle sensor measures temperature of intake air that flows through aspirator to passenger
room. The sensor uses a thermistor which is sensitive to the change in temperature. The elec-
trical resistance of the thermistor decreases as temperature increases.

Mode door motor (Front)

The mode door (front) controls the direction the conditioned air passes through the ventilation
system. Through a series of levers and gears, the mode door controls the defrost door, the foot
door, and the vent door. There are 5 preset positions: VENT, B/L, FOOT, D/F and DEF. The
FOOT position can be set to allow some airflow through to the defroster vent or to completely
block the defroster vent using the CONSULT. The mode door motor receives position com-
mands from the A/C auto amp. and reports actual door position back via an LCU (Local Control
Unit) installed inside the motor. Commands and responses are sent across the LIN (Local In-
terconnect Network) to each motor simultaneously, with each motor having its own unique ad-
dress, thereby only responding to requests sent to its specific address. The LCU reads the door
position from a Position Balanced Resistor (PBR), also part of the motor, and returns that infor-
mation to the front air control. The LCU switches the polarity of the circuits connected to the DC
motor to drive the motor forward or backward as requested by the front air control. The mode
door has 5 expected positions and, therefore, can set up to 5 DTCs if the expected position is
not reported back to the A/C auto amp.

Refrigerant pressure sensor

Refer to

EC-27, "Refrigerant Pressure Sensor"

.

Sunload sensor

Sunload sensor measures sunload amount.This sensor converts sunload amount to voltage
signal by photodiode and transmits to A/C auto amp.

Component

Description

COMPONENT PARTS

HAC-15

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

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REAR AUTOMATIC AIR CONDITIONING SYSTEM : Component Parts Location

INFOID:0000000009176779

1.

Rear blower motor relay (view with
instrument panel removed)

2.

PTC relay 1

3.

PTC relay 2

4.

Rear air control

5.

A/C switch assembly (with base au-
dio system)

6.

A/C auto amp.

7.

A/C display unit (with base audio
system)

8.

Display unit (except base audio sys-
tem)

9.

A/C and AV switch assembly (except
base audio system)

10. A/C auto amp.

11. AV control unit (except base audio

system)

12. BCM (view with combination meter

removed)

ALIIA0684ZZ

HAC-16

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

COMPONENT PARTS

REAR AUTOMATIC AIR CONDITIONING SYSTEM : Component Description

INFOID:0000000009176780

13. Air mix door motor (rear) (view with

front A/C assembly removed from
vehicle)

14. PTC heater (view with rear booster

assembly removed from vehicle)

15. Rear blower motor resistor 1

16. Rear blower motor 1

17. Rear shut-off door motor (view with

rear booster assembly removed from
vehicle)

18. Mode door motor (rear)

19. Rear blower motor resistor 2 (view

with luggage side lower finisher RH
removed)

20. Rear blower motor 2

Component

Description

A/C auto amp.

A/C auto amp. controls the automatic air conditioning system by inputting and calculating
signals from each sensor and each switch.

A/C display unit
(with base audio system)

The A/C display unit indicates operation status of the front and rear automatic air condition-
ing system.

A/C switch assembly
(with base audio system)

The A/C switch assembly controls the operation of the A/C and heating system based on
inputs from the temperature control knob, the mode switches, the blower control dial, the
ambient temperature sensor, the intake sensor, and inputs received from the ECM via CAN
communication. Diagnosis of the A/C switch assembly can be performed using the CON-
SULT. There is no self-diagnostic feature available.

A/C and AV switch assembly
(except base audio system)

Rear air control operation signal is transmitted from the A/C and AV switch assembly to AV
control unit via communication line.

Air mix door motor (Rear)

The air mix door (rear) controls the mix of hot or cold air that enters the ventilation system.
It is controlled by the A/C auto amp. based on the position of the temperature dial. The air
mix door motor (rear) receives position commands from the A/C auto amp. and reports ac-
tual door position back via an LCU (Local Control Unit) installed inside the motor. Com-
mands and responses are sent across the LIN (Local Interconnect Network) to each motor
simultaneously, with each motor having its own unique address, thereby only responding to
requests sent to its specific address. The LCU reads the door position from a Position Bal-
anced Resistor (PBR), also part of the motor, and returns that information to the A/C auto
amp. The LCU switches the polarity of the circuits connected to the DC motor to drive the
motor forward or backward as requested by the front air control. If the air mix door (rear)
moves to a position less than 5% or more than 95% of its expected or allowed positions, the
A/C auto amp. will set a DTC.

AV control unit

AV control unit transmits A/C and AV switch assembly operation signal to A/C auto amp. via
CAN communication line.

BCM

BCM transmits blower motor ON signal to the rear blower motor relay.

Display unit (except base audio system)

The display unit indicates operation status of the front and rear automatic air conditioning
system.

Mode door motor (Rear)

The mode door (rear) controls the direction the conditioned air passes through the ventila-
tion system. The mode door motor (rear) receives position commands from the A/C auto
amp. and reports actual door position back via an LCU (Local Control Unit) installed inside
the motor. Commands and responses are sent across the LIN (Local Interconnect Network)
to each motor simultaneously, with each motor having its own unique address, thereby only
responding to requests sent to its specific address. The LCU reads the door position from a
Position Balanced Resistor (PBR), also part of the motor, and returns that information to the
front air control. The LCU switches the polarity of the circuits connected to the DC motor to
drive the motor forward or backward as requested by the A/C auto amp. The mode door has
2 expected positions and, therefore, can set up to 2 DTCs if the expected position is not re-
ported back to the A/C auto amp.

PTC heater

The positive temperature coefficient (PTC) heater provides supplemental heat to the rear
seating by warming the air as it flows through its electrically controlled heating grid.

PTC heater relay

The PTC heater relay controls the flow of current to the PTC heater. The relay is controlled
by the A/C auto amp.

Rear blower motor 1

The rear blower motor-1 varies the speed at which the air flows through the ventilation sys-
tem.