AIR CONDITIONING SYSTEM - IG Power Source Circuit

DESCRIPTION

The main power source is supplied to the A/C amplifier when the engine switch on (IG).

The power source is used for operating the A/C amplifier and servo motor, etc.

Air Conditioning System - Ig Power Source Circuit. AIR CONDITIONING. Lexus IS250 IS220d GSE20 ALE20

Start the engine before inspection. Check the IG1 relay or battery if the engine does not start.

1.INSPECT FUSE (ECU-IG LH)

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

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

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

3.CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BATTERY)

Disconnect the A/C amplifier connector.

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

Standard voltage:
Tester Connection Condition Specified Condition
J58-21 (IG+) - Body ground Engine switch off Below 1 V
Engine switch on (IG) 10 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BODY GROUND)

Disconnect the A/C amplifier connector.

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

Standard resistance:
Tester Connection Condition Specified Condition
J58-20 (GND) - Body ground Always Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE AIR CONDITIONING AMPLIFIER

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