Nissan Primera P12. Instruction — part 20
TROUBLE DIAGNOSIS
ATC-73
C
D
E
F
G
H
I
K
L
M
A
B
ATC
Blower Motor Circuit
EJS002Y2
SYMPTOM:
●
Blower motor operation is malfunctioning.
●
Blower motor operation is malfunctioning under out of starting fan speed control.
INSPECTION FLOW
*1
ATC-48, "Self-diagnosis Function"
*2
ATC-100, "Ambient Sensor Circuit"
*3
ATC-102, "In-vehicle Sensor Circuit"
*4
ATC-105, "Sunload Sensor Circuit"
*5
ATC-67, "Air Mix Door Motor Circuit"
*6
ATC-49, "FUNCTION CONFIRMA-
TION PROCEDURE"
,see No.14.
*7
ATC-75, "DIAGNOSTIC PROCE-
DURE FOR BLOWER MOTOR"
*8
ATC-49, "FUNCTION CONFIRMA-
TION PROCEDURE"
,see No.5 or 7.
*9
RJIA0784E
ATC-74
TROUBLE DIAGNOSIS
SYSTEM DESCRIPTION
Component Parts
Fan speed control system components are:
●
Auto amp.
●
A/C LAN system (PBR built-in air mix door motor, mode door motor and intake door motor)
●
Fan control amp.
●
In-vehicle sensor
●
Ambient sensor
●
Sunload sensor
●
Intake sensor
System Operation
Automatic Mode
In the automatic mode, the blower motor speed is calculated by the automatic amplifier based on input from
the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor.
The blower motor applied voltage ranges from approximately 4 volts (lowest speed) to 12 volts (highest
speed).
The control blower speed (in the range of 4 to 12V), the automatic amplifier supplies a gate voltage to the fan
control amplifier. Based on this voltage, the fan control amplifier controls the voltage supplied to the blower
motor.
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)
*10
*11
*12
ATC-108, "Intake Sensor Circuit"
*13 YD engine:
F9Q engine: EC-F9Q-17
RJIA0785E
TROUBLE DIAGNOSIS
ATC-75
C
D
E
F
G
H
I
K
L
M
A
B
ATC
The blower will begin operation momentarily after the A/C button 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
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
low speed is usual low speed (approx. 4V). During high sunload conditions, the auto amp causes the blower
fan speed to increase. (Approx. 7V)
Fan Speed Control Specification
COMPONENT DESCRIPTION
Fan Control Amplifier
The fan control amplifier is located on the heater & cooling unit. The
fan control amp. receives a gate voltage from the auto amp. to step-
lessly maintain the blower fan motor voltage in the 4 to 12 volt range.
DIAGNOSTIC PROCEDURE FOR BLOWER MOTOR
SYMPTOM: Blower motor operation is malfunctioning under starting
fan speed control.
RJIA0522E
RHA625H
RJIA2346E
ATC-76
TROUBLE DIAGNOSIS
1.
CHECK POWER SUPPLY FOR BLOWER MOTOR
Disconnect blower motor harness connector.
OK or NG
OK
>> GO TO 2.
NG
>> Check power supply circuit and 15A fuses (Nos. 14 and
16, located in the fuse block). Refer to
TION POWER SUPPLY — IGNITION SW. IN “ON” AND/OR “START”"
.
●
If OK, check for open circuit in wiring harness. Repair or replace as necessary.
●
If NG, replace fuse and check wiring harness for short circuit. Repair or replace as necessary.
2.
CHECK FAN FEED BACK CIRCUIT
OK or NG
OK
>> GO TO 3.
NG
>> Repair harness or connector.
3.
CHECK BLOWER MOTOR
Refer to
ATC-78, "COMPONENT INSPECTION"
.
OK or NG
OK
>> GO TO 4.
NG
>> Replace blower motor.
4.
CHECK POWER SUPPLY FOR FAN CONTROL AMP.
1.
Reconnect blower motor connector.
2.
Disconnect fan control amp. harness connector.
OK or NG
OK
>> GO TO 5.
NG
>> Repair harness or connector.
Terminal
Voltage
(+)
(
−
)
Blower motor con-
nector
Terminal No.
(Wire color)
M74
1 (L/W)
Ground
Approx. 12V
RJIA0524E
Terminal
Condition
Voltage
(+)
(
−
)
Auto amp.
connector
Terminal No.
(Wire color)
M76
34 (L/B)
Ground
Fan speed: 1st
Approx. 8V
RJIA0787E
Terminal
Voltage
(+)
(
−
)
Fan control amp.
connector
Terminal No.
(Wire color)
M45
3 (L/B)
Ground
Approx. 12V
RJIA0526E
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