Toyota 4Runner manuals

Toyota 4Runner: Air Conditioning Compressor Magnetic Clutch Circuit

DESCRIPTION

When the air conditioning amplifier assembly is turned on, a magnet clutch assembly 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

Battery voltage is applied to terminals 1 and 2

Below 1 Ω


NG

REPLACE MAGNET CLUTCH RELAY (A/C COMP)

OK

2.

INSPECT COOLER COMPRESSOR ASSEMBLY

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



(b) Disconnect the A magnet clutch connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 (MG+) - A-1

Always

Below 1 Ω

3 (MG+) - Body ground

Always

10 kΩ or higher


NG

REPLACE COOLER COMPRESSOR ASSEMBLY

OK

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.


NG

REPLACE MAGNET CLUTCH ASSEMBLY

OK

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

*1

A/C COMP Relay

*a

Component without relay installed

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


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

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)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

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.

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

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


OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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