Air Conditioning System Ig Power Source Circuit

Heater & Air Conditioning System. Lexus Gs430, Gs300. Uzs190 Grs190
Air Conditioning. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT FUSE (ECU-IG RH)

INSPECT AIR CONDITIONING AMPLIFIER (IG+ - GND)

CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BATTERY)

CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BODY GROUND)

AIR CONDITIONING SYSTEM - IG Power Source Circuit


DESCRIPTION

The main power source is supplied to the A/C amplifier when the engine switch is on (IG).
The power source is used for operating the A/C amplifier and servomotor, etc.

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System.Air Conditioning System Ig Power Source Circuit


INSPECTION PROCEDURE

HINT:
Start the engine before inspection. Check the IG1 relay or battery if the engine does not start.
1.INSPECT FUSE (ECU-IG RH)

  1. Remove the ECU-IG RH fuse from the cowl side junction block RH.

  1. Measure the resistance of the fuse.


Standard resistance:

Tester Item
Condition
Specified Condition
ECU-IG RH fuse
Always
Below 1 Ω


NG
CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE
OK


2.INSPECT AIR CONDITIONING AMPLIFIER (IG+ - GND)
Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System.Air Conditioning System Ig Power Source Circuit

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

  1. Turn the engine switch on (IG).

  1. Measure the voltage of the connector.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    L52-21 (IG+) - L52-20 (GND)
    		Engine switch on (IG)
    		10 to 14 V


NG
Go to step 3
OK

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

3.CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BATTERY)
Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System.Air Conditioning System Ig Power Source Circuit

  1. Disconnect the L52 A/C amplifier connector.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    L52-21 (IG+) - Body ground
    		Engine switch off
    		Below 1.0 V
    Engine switch on (IG)
    		10 to 14 V


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


4.CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BODY GROUND)
Lexus Gs430, Gs300. Uzs190 Grs190.Air Conditioning.Air Conditioning System.Air Conditioning System Ig Power Source Circuit

  1. Disconnect the L52 A/C amplifier connector.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    L52-20 (GND) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER