AIR CONDITIONING SYSTEM > Blower Motor Circuit

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DESCRIPTION

E107334E01
The blower motor is operated by signals from the A/C amplifier. Blower motor speed signals are transmitted by changes in the duty ratio.
Duty Ratio:
The duty ratio is the ratio of the blower motor ON time (A) to the total of the blower motor ON and OFF time (A + B).
The blower motor controller controls the blower motor speed.

WIRING DIAGRAM


E107333E01


INSPECTION PROCEDURE

1.PERFORM ACTIVE TEST BY INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and push the intelligent tester main switch on.

  1. Select the item below in the Active Test and then check that the relay operates.


A/C amplifier: 
Item
Test Details / Display
(Range)
Diagnostic Note
Blower Motor
(Blower Motor)
Blower motor /
Min.: Level 0, Max.: Level 31
-

Result: 
OK
A
NG (blower motor does not operate)
B
NG (blower motor operates but does not change speed)
C


B
Go to step 2

C
Go to step 6
A

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

2.INSPECT FUSE

  1. Remove the HEATER fuse and ALT fuse from the engine room No. 1 junction block.
    Measure the resistance of the fuses.


Standard resistance:

Tester Item
Condition
Specified Condition
HEATER fuse
Always
Below 1 Ω
ALT fuse
Always
Below 1 Ω



NG
REPLACE FUSE
OK


3.CHECK WIRE HARNESS (BLOWER MOTOR - BODY GROUND)
E107335E05

  1. Disconnect the A50 or k1 blower motor connector.

  1. Measure the resistance of the wire harness side connector.

    Standard resistance:
    Tester Item
    		Condition
    		Specified Condition
    A50-1 (GND) *1 - Body ground
    		Always
    		Below 1 Ω
    k1-1 (GND) *2 - Body ground
    		Always
    		Below 1 Ω

    HINT:
    1. *1: 3GR-FE, 3GR-FSE
    2. *2: 3UZ-FE



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


4.CHECK WIRE HARNESS (BLOWER MOTOR - BATTERY)
E107335E06

  1. Disconnect the A50 or k1 blower motor connector.

  1. Measure the voltage of the wire harness side connector.

    Standard voltage:
    Tester Item
    		Condition
    		Specified Condition
    A50-3 (+B) *1 - Body ground
    		Engine switch on (IG)
    		10 to 14 V
    k1-3 (+B) *2 - Body ground
    		Engine switch on (IG)
    		10 to 14 V

    HINT:
    1. *1: 3GR-FE, 3GR-FSE
    2. *2: 3UZ-FE



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


5.CHECK BLOWER MOTOR
E109710E01

  1. Disconnect the A/C amplifier connector.

  1. Connect the blower motor connector.

  1. Measure the voltage of the connector.

    Standard voltage:
    Tester Item
    		Condition
    		Specified Condition
    2 (SI) - Body ground
    		Engine switch on (IG)
    		4.5 to 5.5 V



NG
REPLACE BLOWER MOTOR
OK


6.CHECK WIRE HARNESS (A/C AMPLIFIER - BODY GROUND)
E107331E05

  1. Disconnect the L52 A/C amplifier connector.

  1. Measure the voltage of the wire harness side connector.

    Standard voltage:
    Tester Item
    		Condition
    		Specified Condition
    L52-11 (BLW) - Body ground
    		Engine switch on (IG)
    		4.5 to 5.5 V



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


7.CHECK AIR CONDITIONING AMPLIFIER
E107542E02

  1. Remove the A/C amplifier with its connectors still connected.

  1. Turn the engine switch on (IG).

  1. Turn the blower switch ON (Lo).

  1. Measure the waveform between terminal L52-11 (BLW) of the A/C amplifier and body ground.

    OK:
    Waveform is as shown in the illustration.

    HINT:
    Waveform varies with the blower level.

Item
Contents
Tool setting
2 V / DIV., 500 μs / DIV.
Vehicle condition
Engine switch on (IG)
Blower switch ON (Lo)


NG
REPLACE AIR CONDITIONING AMPLIFIER
OK

REPLACE BLOWER MOTOR