Nissan Titan. Manual - part 384

DEFROSTER DOOR MOTOR CIRCUIT

HAC-41

< DTC/CIRCUIT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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HAC

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1. Check continuity between front air control harness connector

M49 (A) terminal 10 and defroster door motor harness connec-

tor M144 (B) terminal 4.

2. Check continuity between front air control harness connector

M49 terminal 10 and ground.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Repair or replace harness as necessary.

6.

CHECK FRONT AIR CONTROL FOR 5 VOLT REFERENCE (VREF), VREF RETURN, AND FEEDBACK

SIGNAL 

1. Reconnect front air control harness connectors.

2. Turn ignition switch ON.

3. Check voltage between front air control harness connector M49

(B) terminal 3, and M50 (A) terminal 28.

4. Check voltage between front air control harness connector M49

terminal 10 and ground.

Is the inspection result normal?

YES

>> GO TO 7.

NO

>> Replace front air control. Refer to 

VTL-8, "Removal and

Installation"

.

7.

CHECK FRONT AIR CONTROL FOR FEEDBACK SIGNAL 

A

B

Continuity

Connector

Terminal

Connector

Terminal

M49

10

M144

4

Yes

AWIIA0410ZZ

Connector

Terminal

—

Continuity

M49

10

Ground

No

AWIIA0409ZZ

A

B

Connector

Terminals

Connector

Terminals

Voltage (Approx.)

(+)

(-) 

M50

28

M49

3

5 Volts

AWIIA0407ZZ

Connector

Terminal

—

Voltage (Approx.)

M49

10

Ground

0 Volts

AWIIA0408ZZ

HAC-42

< DTC/CIRCUIT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

DEFROSTER DOOR MOTOR CIRCUIT

1. Reconnect the defroster door motor harness connector M144.

2. Check voltage between front air control harness connector M49

terminal 10 and ground.

Is the inspection result normal?

YES

>> Inspect defroster door for binding or mechanical failure.

If defroster door moves freely, replace front air control.

Refer to 

VTL-8, "Removal and Installation"

.

NO

>> Replace the defroster door motor. Refer to 

VTL-17,

"Removal and Installation"

.

Connector

Terminal

—

Voltage (Approx.)

M49

10

Ground

0.2 to 4.8 Volts

AWIIA0408ZZ

BLOWER MOTOR CONTROL SYSTEM

HAC-43

< DTC/CIRCUIT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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BLOWER MOTOR CONTROL SYSTEM

System Description

INFOID:0000000009882462

SYSTEM DESCRIPTION

Component Parts

Blower speed control system components are:

• Front air control

• Variable blower control

• Front blower motor relay

• Front blower motor

• In-vehicle sensor

• Ambient sensor

• Optical sensor

• Intake sensor

System Operation

Automatic Mode

In the automatic mode, the blower motor speed is calculated by the front air control and variable blower control

based on input from the in-vehicle sensor, optical sensor, intake sensor and ambient sensor, and potentio tem-

perature control (PTC). 

When the air flow is increased, the blower motor speed is adjusted gradually to prevent a sudden increase in

air flow.

In addition to manual air flow control and the usual automatic air flow control, starting air flow control, low

water temperature starting control and high passenger compartment temperature starting control are avail-

able.

Starting Blower Speed Control

Start up from cold soak condition (Automatic mode).

In a cold start up condition where the engine coolant temperature is below 50

°C (122°F), the blower will not

operate at blower speed 1 for a short period of time (up to 210 seconds). The exact start delay time varies

depending on the ambient and engine coolant temperatures.

In the most extreme case (very low ambient temperature) the blower starting delay will be 210 seconds as

described above. After the coolant temperature reaches 50

°C (122°F), or the 210 seconds has elapsed, the

blower speed will increase to the objective blower speed.

Start up from usual operating or hot soak condition (Automatic mode).

The blower will begin operation momentarily after the AUTO switch is pushed. The blower speed will gradually

rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective

blower speed).

Blower Speed Compensation - Sunload

AWIIA0411GB

HAC-44

< DTC/CIRCUIT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

BLOWER MOTOR CONTROL SYSTEM

When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low

speed. The speed will vary depending on the sunload. During conditions of low or no sunload, the blower

operates at low speed. During high sunload conditions, the front air control causes the blower speed to

increase.

Blower Speed Control Specification

COMPONENT DESCRIPTION

Variable Blower Control

The variable blower control is located on the cooling unit. The vari-

able blower control receives a gate voltage from the front air control

to steplessly maintain the blower motor voltage in the 0 to 5 volt

range (approx.).

Front Blower Motor Component Function Check

INFOID:0000000009882463

INSPECTION FLOW

1.

CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - FRONT BLOWER

1. Rotate the blower control dial clockwise once. Blower motor should operate in low speed.

2. Rotate the blower control dial clockwise, and continue checking blower speed until all speeds are

checked.

Is the inspection result normal?

YES

>> Inspection End.

NO

>> Go to diagnosis procedure. Refer to 

HAC-44, "Front Blower Motor Diagnosis Procedure"

.

Front Blower Motor Diagnosis Procedure

INFOID:0000000009882464

Regarding Wiring Diagram information, refer to 

HAC-71, "Wiring Diagram - Automatic Air Conditioner"

.

SYMPTOM: Blower motor operation is malfunctioning.

DIAGNOSTIC PROCEDURE FOR BLOWER MOTOR

WJIA0441E

WJIA0559E