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 | .gif) |
REPLACE MAGNET CLUTCH RELAY (A/C COMP) |
|
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|
2. |
INSPECT COOLER COMPRESSOR ASSEMBLY |
|
(a) Remove the cooler compressor assembly (See page
|
|
.gif)
).
(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 |
|
|
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 |
|
|
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 |
|
*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 |
|
|
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 |
|
*a |
Front view of wire harness connector (to Air Conditioning Amplifier Assembly) |
| NG | |
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.
(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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DESCRIPTION
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ON-VEHICLE INSPECTION
PROCEDURE
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switch is turned to ON.
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