Your Vehicle: 2009 Nissan-Datsun Altima V6-3.5L (VQ35DE)
 
Vehicle » Heating and Air Conditioning » Testing and Inspection » Component Tests and General Diagnostics » Blower Motor » Diagnosis Procedure » Automatic Air Conditioner  
 
 
  Automatic Air Conditioner  
 

BLOWER MOTOR

Description

SYSTEM DESCRIPTION

Component Parts

Fan speed control system components are:

  • Front air control
  • A/C LAN system (PBR built-in mode door motor, air mix door motors and intake door motor)
  • In-vehicle sensor
  • Ambient sensor
  • Sunload sensor
  • Intake sensor
  • Fan control amp.

System Operation

  

Automatic Mode
In the automatic mode, the blower motor speed is calculated by the front air control based on the input from the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor.
When the air flow is increased, the duty ratio of the blower fan motor's drive signal is changed at 8%/sec. 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 available.

Starting Fan Speed Control
Start up from COLD SOAK Condition (Automatic mode)
In a cold start up condition where the engine coolant temperature is below 56°C (133°F) , the blower will not operate for a short period of time (up to 150 seconds). The exact start delay time varies depending on the ambient and engine coolant temperature.
In the most extreme case (very low ambient) the blower starting delay will be 150 seconds as described above. After this delay, the blower will operate at low speed until the engine coolant temperature rises above 56 °C (133°F), at which time the blower speed will increase to the objective speed.
Start up from usual or HOT SOAK Condition (Automatic mode)
The blower will begin operation momentarily after the AUTO switch is pressed. 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
When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low speed. The low speed will vary depending on the sunload. During conditions of low or no sunload, the blower speed is at duty ratio 25%. During high sunload conditions, the front air control. raise the blower speed (duty ratio 49%).

Blower Speed Control Specification

  

BLOWER MOTOR

Diagnosis Procedure

SYMPTOM: Blower motor operation is malfunctioning.

DIAGNOSIS PROCEDURE FOR BLOWER MOTOR
SYMPTOM: Blower motor operation is malfunctioning under starting blower speed control.

  

1.CHECK POWER SUPPLY FOR BLOWER MOTOR

  1. Disconnect fuse block (J/B) connector.

  

  1. Press ignition switch ON.
  2. Check voltage between fuse block (J/B) harness connector E6 terminal P6 and ground.

  

Is the Inspection result normal?
YES >> GO TO 2
NO >> Check power supply circuit and 15A fuses [Nos. 21 and 22, located in the fuse block (J/B)].

  • If OK, check for open circuit in wiring harness. Repair or replace as necessary.
  • If OK, check fuses and check wiring harness for possible open or short circuit.
  • If OK, GO TO 5 2.CHECK BODY GROUND CIRCUIT FOR BLOWER MOTOR

  

  1. Disconnect blower motor connector.
  2. Press ignition switch OFF.
  3. Check continuity between blower motor harness connector M31 terminal 1 and ground.

  

Is the Inspection result normal?
YES >> Reconnect blower motor harness connector and GO TO
3
NO >> Repair harness or connector.
3.CHECK BLOWER MOTOR CONTROL CIRCUIT BETWEEN BLOWER MOTOR AND FRONT AIR CONTROL

  1. Disconnect front air control harness connector.

  

  1. Check continuity between blower motor harness connector M31 (A) terminal 3 and front air control harness connector M37 (B) terminal 1.

  

Is the Inspection result normal?
YES >> GO TO 4
NO >> Repair harness or connector.
4.CHECK POWER SUPPLY FOR FRONT AIR CONTROL

  1. Press ignition switch ON.

  

  1. Check voltage between front air control harness connector M37 terminals 39, 19, 40 and ground.

  

Is the Inspection result normal?
YES >> 1. Replace front air control. Refer to See: Control Module HVAC\Service and Repair.

  1. Confirm that blower motor operation is normal. NO >>
    • Check for open circuit in wiring harness. Repair or replace as necessary.
    • If OK, replace fuse and check wiring harness for short circuit. Repair or replace an necessary.

5.CHECK POWER SUPPLY FOR FRONT BLOWER MOTOR RELAY

  

  1. Connect fuse block (J/B) connector.
  2. Press ignition switch ON.
  3. Turn blower motor control dial to any speed except OFF.
  4. Check voltage between fuse block (J/B) E6 terminal 6P and ground.

6P - Ground : Battery Voltage

Is the Inspection result normal?
YES >> GO TO 9
NO >> GO TO 6
6.CHECK POWER SUPPLY FOR FRONT BLOWER MOTOR RELAY FOR AN OPEN

  

  1. Press ignition switch OFF.
  2. Disconnect BCM harness connector M19.
  3. Disconnect fuse block (J/B) connector.
  4. Check continuity between BCM harness connector M19 (A) terminal 90 and fuse block (J/B) harness connector E6 (B) terminal 6P.

  

Is the Inspection result normal?
YES >> GO TO 7
NO >> Repair harness or connector.
7.CHECK BLOWER FAN SWITCH SIGNAL FOR VOLTAGE

  1. Disconnect BCM harness connector M18.

  

  1. Press ignition switch ON.
  2. Check voltage between BCM harness connector M18 terminal 55 and ground.

  

Is the Inspection result normal?
YES >> Replace BCM. Refer to See: Body and Frame\Body Control Systems\Body Control Module\Service and Repair.
NO >> GO TO 8
8.CHECK BLOWER FAN SWITCH SIGNAL CIRCUIT FOR AN OPEN

  

  1. Press ignition switch OFF.
  2. Disconnect front air control harness connector.
  3. Check continuity between BCM harness connector M18 (A) terminal 55 and front air control harness connector M37 (B) terminal 24.

  

Is the Inspection result normal?
YES >> Replace front air control. Refer to See: Control Module HVAC\Service and Repair.
NO >> Repair harness or connector.
9.CHECK FRONT BLOWER MOTOR RELAY GROUND

  

  1. Press ignition switch OFF.
  2. Disconnect fuse block (J/B) harness connector M5.
  3. Check continuity between fuse block (J/B) harness connector M5 terminal 7M and ground.

  

Is the Inspection result normal?
YES >> Replace front blower motor relay.
NO >> Repair harness or connector.