Toyota 4Runner: Air Conditioning Compressor Magnetic Clutch Circuit

Toyota 4Runner Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System(for Manual Air Conditioning System) / Air Conditioning Compressor Magnetic Clutch Circuit

DESCRIPTION

When the air conditioning amplifier assembly is turned on, a magnet clutch assembly ON signal is sent from the MGC terminal of the air conditioning amplifier assembly. Then, the A/C COMP relay turns on to operate the magnet clutch assembly.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.	INSPECT MAGNET CLUTCH RELAY (A/C COMP)

(a) Remove the A/C COMP relay from the engine room No. 1 relay block, junction block.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
3 - 5	Battery voltage is not applied to terminals 1 and 2	10 kΩ or higher
3 - 5	Battery voltage is applied to terminals 1 and 2	Below 1 Ω

REPLACE MAGNET CLUTCH RELAY (A/C COMP)

2.	INSPECT COOLER COMPRESSOR ASSEMBLY

(a) Remove the cooler compressor assembly (See page ).

(b) Disconnect the A magnet clutch connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
3 (MG+) - A-1	Always	Below 1 Ω
3 (MG+) - Body ground	Always	10 kΩ or higher

REPLACE COOLER COMPRESSOR ASSEMBLY

3.	INSPECT MAGNETIC CLUTCH ASSEMBLY

(a) Reconnect the A magnet clutch connector.

(b) Apply battery voltage to the magnet clutch assembly and check the operation of the magnet clutch assembly.

OK:

Measurement Condition	Specified Condition
Battery positive (+) → Terminal 3 (MG+) Battery negative (-) → Body ground	Magnet clutch assembly operating sound can be heard, and magnetic clutch hub and rotor lock.

Measurement Condition

Specified Condition

Battery positive (+) → Terminal 3 (MG+)

Battery negative (-) → Body ground

Magnet clutch assembly operating sound can be heard, and magnetic clutch hub and rotor lock.

REPLACE MAGNET CLUTCH ASSEMBLY

4.	CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK, JUNCTION BLOCK - BATTERY)

(a) Remove the A/C COMP relay from the engine room No. 1 relay block, junction block.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A/C COMP relay terminal 1 - Body ground	Ignition switch ON	11 to 14 V
A/C COMP relay terminal 5 - Body ground	Always	11 to 14 V

Text in Illustration

A/C COMP Relay

Component without relay installed

(Engine Room No. 1 Relay Block, Junction Block)

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BATTERY)

(a) Disconnect the F42 amplifier connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F42-20 (MGC) - Body ground	Ignition switch off	Below 1 V
F42-20 (MGC) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to Air Conditioning Amplifier Assembly)

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK, JUNCTION BLOCK - COOLER COMPRESSOR)

(a) Remove the A/C COMP relay from the engine room No. 1 relay block, junction block.

(b) Disconnect the B41 compressor connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A/C COMP relay terminal 3 - B41-3 (MG+)	Always	Below 1 Ω
B41-3 (MG+) - Body ground	Always	10 kΩ or higher

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPAIR OR REPLACE HARNESS OR CONNECTOR

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