Compressor Circuit

AIR CONDITIONING: AIR CONDITIONING SYSTEM: Compressor Circuit

Compressor Circuit

DESCRIPTION

The A/C amplifier outputs the magnet clutch ON signal to the ECM by way of MPX line. The ECM receives this signal, and it sends a signal from terminal ACMG to the magnet clutch relay, turning the magnet clutch ON.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK ECM (ACMG VOLTAGE)




(a) Remove ECM but do not disconnect the connector.
(b) Start the engine and push the AUTO switch.
(c) Measure the voltage of the connector when the magnet clutch is operated by the A/C switch.
Standard voltage:






OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG -- Continue to next step.
2. INSPECT FUSE (HEATER)
(a) Remove the HEATER fuse from the driver side junction block.
(b) Measure the resistance of the fuse.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
3. INSPECT RELAY (Marking: A/C COMP)




(a) Remove the A/C COMP relay from the engine room No. 2 relay block.
(b) Measure the resistance of the relay.
Standard resistance:






NG -- REPLACE RELAY
OK -- Continue to next step.
4. INSPECT MAGNET CLUTCH ASSEMBLY




(a) Disconnect the A2 clutch connector.
(b) Apply battery voltage to the clutch and check operation of the clutch.
OK:






NG -- REPLACE MAGNET CLUTCH ASSEMBLY
OK -- Continue to next step.
5. CHECK WIRE HARNESS (ENGINE ROOM NO. 2 RELAY BLOCK - MAGNET CLUTCH,
ECM AND BATTERY)




(a) Remove the A/C COMP relay from the engine room No. 2 relay block.
(b) Disconnect the A2 clutch connector.
(c) Disconnect the E5 ECM connector.
(d) Measure the voltage of the wire harness side connector.
Standard voltage:





(e) Measure the resistance of the wire harness side connector.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM