Air Conditioning System Blower Motor Circuit

Heater & Air Conditioning System. Lexus Is250, Is220D. Gse20 Ale20
Air Conditioning. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

PERFORM ACTIVE TEST BY INTELLIGENT TESTER

INSPECT FUSE

CHECK WIRE HARNESS (BLOWER MOTOR - BODY GROUND)

CHECK WIRE HARNESS (BLOWER MOTOR - BATTERY)

INSPECT BLOWER MOTOR

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

INSPECT AIR CONDITIONING AMPLIFIER

AIR CONDITIONING SYSTEM - Blower Motor Circuit


DESCRIPTION

Lexus Is250, Is220D. Gse20 Ale20.Air Conditioning.Air Conditioning System.Air Conditioning System Blower Motor Circuit
The blower motor is operated by signals from the A/C amplifier. The blower motor speed is controlled using various duty ratios.
Duty Ratio:
  1. 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).
  2. The blower motor controller controls the blower motor speed.

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Air Conditioning.Air Conditioning System.Air Conditioning System Blower Motor Circuit


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 turn the intelligent tester main switch on.

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


Active Test / Air Conditioner:
Item
Test Details / Display (Range)
Diagnostic Note
Blower Motor
(Blower Motor)
Blower motor / Min.: Level 01, Max.: Level 31
-

Result:

Result
Proceed to
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
Lexus Is250, Is220D. Gse20 Ale20.Air Conditioning.Air Conditioning System.Air Conditioning System Blower Motor Circuit

  1. Remove the HEATER fuse from the engine room R/B and J/B No. 1.

  1. Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester Item
    		Condition
    		Specified Condition
    HEATER fuse
    		Always
    		Below 1 Ω


NG
REPLACE FUSE (HEATER)
OK


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


    Lexus Is250, Is220D. Gse20 Ale20.Air Conditioning.Air Conditioning System.Air Conditioning System Blower Motor Circuit

  1. Disconnect the blower motor connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    4GR-FSE:
    Tester Connection
    		Condition
    		Specified Condition
    A34-1 (GND) - Body ground
    		Always
    		Below 1 Ω
    2AD-FHV:
    Tester Connection
    		Condition
    		Specified Condition
    b1-1 (GND) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4.CHECK WIRE HARNESS (BLOWER MOTOR - BATTERY)


    Lexus Is250, Is220D. Gse20 Ale20.Air Conditioning.Air Conditioning System.Air Conditioning System Blower Motor Circuit

  1. Disconnect the blower motor connector.

  1. Measure the voltage according to the value(s) in the table below.

    Standard voltage:
    4GR-FSE:
    Tester Connection
    		Condition
    		Specified Condition
    A34-3 (+B) - Body ground
    		Always
    		10 to 14 V
    2AD-FHV:
    Tester Connection
    		Condition
    		Specified Condition
    b1-3 (+B) - Body ground
    		Always
    		10 to 14 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5.INSPECT BLOWER MOTOR


    Lexus Is250, Is220D. Gse20 Ale20.Air Conditioning.Air Conditioning System.Air Conditioning System Blower Motor Circuit

  1. Disconnect the A/C amplifier connector.

  1. Connect the blower motor connector.

  1. Measure the voltage according to the value(s) in the table below.

    Standard voltage:
    4GR-FSE:
    Tester Connection
    		Condition
    		Specified Condition
    A34-2 (SI) - Body ground
    		Engine switch on (IG)
    		4.5 to 5.5 V
    2AD-FHV:
    Tester Connection
    		Condition
    		Specified Condition
    b1-2 (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)


    Lexus Is250, Is220D. Gse20 Ale20.Air Conditioning.Air Conditioning System.Air Conditioning System Blower Motor Circuit

  1. Disconnect the A/C amplifier connector.

  1. Measure the voltage according to the value(s) in the table below.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    J58-11 (BLW) - Body ground
    		Engine switch on (IG)
    		4.5 to 5.5 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


7.INSPECT AIR CONDITIONING AMPLIFIER


    Lexus Is250, Is220D. Gse20 Ale20.Air Conditioning.Air Conditioning System.Air Conditioning System Blower Motor Circuit

  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 J58-11 (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
1 V/DIV., 500 μs/DIV.
Vehicle condition
Engine switch on (IG)
Blower switch ON (Lo)


NG
REPLACE AIR CONDITIONING AMPLIFIER
OK

REPLACE BLOWER MOTOR