Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1080

1A–42 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Magnetic Clutch Diagnosis

D08RY00547

HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–43

When the air conditioning switch and the fan control knob
(fan switch) are turned on with the engine running, current
flows through the thermostat and the compressor relay to
activate the magnetic clutch.
The air conditioning can be stopped by turning of the air
conditioning switch or the fan control knob (fan switch).
However, even when the air conditioning is in operation,
the electronic thermostat, the pressure switch or the

Powertrain Control Module (PCM;V6-3.2L)/ Engine
Control Module (ECM;L4-2.2L) is used to stop the air
conditioning temporarily by turning off the magnetic clutch
in the prearranged conditions to reduce the engine load
which is being caused by the rise in the engine coolant
temperature, and the acceleration of the vehicle, etc.
For the inspection of the relays, switches and units in the
table, refer to “Individual Inspection” in this section.

Magnetic Clutch Does Not Run 

Step

Action

Yes

No

1

Are No. EB-7 (10A) fuse and No. EB-5 (15A) / EB-6 (15A) fuse
OK?

Go to Step 2

Replace

2

Are heater (X-1), thermostat (X-8), and compressor (X-2) relays
OK?

Go to Step 3

Replace

3

Is pressure switch OK?

Go to Step 4

Switch defective

or insufficient

refrigerant.

4

Are air conditioning switch and fan control lever (Fan Switch) OK?

Go to Step 5

Replace

5

1. Turn the ignition switch “ON” (Engine is running).
2. Air conditioning switch and fan control lever (Fan Switch)

“ON”.

3. Check to see if battery voltage is present at chassis side

connector terminal No. E3-1.

Is there a battery voltage?

Go to Step 6

Go to Step 7

6

Check to see if continuity between compressor side connector
terminal No. E3-1 and the magnetic clutch side connector
terminal.

Is there a continuity?

Magnetic clutch

defective.

Compressor

defective.

7

Check to see it battery voltage is present at chassis side
connector terminal No.I24-2.

Is there a battery voltage?

Go to Step 8

Open circuit

between No.EB-7

(10A) fuse and

No. I24-2.

8

Check to see if battery voltage is present at chassis side
connector terminal No. C11-1

Is there a battery voltage?

Go to Step 9

Open circuit

between No.I24-1

and No. C11-1.

9

1. Disconnect thermostat relay (X-8).
2. Check to see if battery voltage is present at the chassis side

relay terminal NO. X8-2

Is there a battery voltage?

Go to Step 10

Open circuit

between No.

EB-7 and C11-2

(10A) fuse and

No.X8-2.

10

Check to see if voltage (approx. 10V) is present between chassis
side relay terminal No. X8-5 and No. X8-3.

Is there a battery voltage?

Go to Step 11

Go to Step 17

11

1. Reconnect thermostat relay and disconnect compressor relay

(X-2).

2. Check to see if battery voltage is present at the chassis side

relay terminal No. X2-5.

Is there a battery voltage?

Go to Step 12

Open circuit

between No.

EB-7 (10A) fuse

and No. X2-5.

12

Check to see if continuity between chassis side relay terminal No.
X2-1 and the chassis side connector terminal No. E3-1.

Is there a continuity?

Go to Step 13

Open circuit.

1A–44 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Magnetic Clutch Does Not Run  (Cont’d)

Step

No

Yes

Action

13

Check to see if battery voltage is present between chassis side
relay terminal No. X2-2 and No. X2-4.

Is there a battery voltage?

Go to Step 14

Go to Step 15

14

Check to see if battery voltage is present at chassis side relay
terminal No. X2-2.

Is there a battery voltage?

Go to Step 16

Open circuit

between No.

EB-7 (10A) fuse

and No. X2-2.

15

Check to see if battery voltage is present at chassis side
connector terminal No. E21-F4 / C1-B14.

Is there a battery voltage?

Power train

control module

(PCM) defective.

Refer to

Driveability and

Emissions in

Engine section.

Open circuit

between No.

X2-4 and No.

E21-F4 / C1-B14.

16

Check to see if continuity between chassis side relay terminal No.
X8-1 and chassis side connector terminal No. E21-F45 / C3-E15.

Is there a continuity?

Power train

control module

(PCM) defective.

Refer to

Driveability and

Emissions in

Engine section.

Open circuit

17

Check to see if battery voltage is present at chassis side relay
terminal No.X8-5.

Is there a battery voltage?

Go to Step 18

Open circuit

between No.X8-5

and C11-2.

18

1. Reconnect thermostat relay.
2. Check to see if battery voltage is present at chassis side

connector terminal No.C40-3.

Is there a battery voltage?

Go to Step 19

Open circuit

between No.I24-1

and No.C40-3.

19

Check to see if battery voltage (appox 10V) is present at chassis
side connector terminal No. C40-1.

Is there a battery voltage?

Go to Step 20

Open circuit

between No.

X8-3 and No.

C40-1.

20

Check to see if continuity between chassis side connector
terminal No. C40-2 and No.I23-6.

Is there a continuity?

Electronic

thermostat

defective.

Open circuit

between No.

C40-2 and

No.I23-6 or poor

ground (Fan

Switch Ground

Circuit).

HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–45

Condenser Fan Diagnosis

While the air conditioning is ON, the cycling switch in the
triple pressure switch senses the refrigerant pressure,
and activates the condenser fan to improve the cooling
capacity of the condenser when the refrigerant pressure

exceeds a set pressure value. The condenser fan stops
when the air conditioning is turned “OFF” or when the
pressure goes down below the set pressure value.

D08RY00548

Condition

Possible cause

Correction

Condenser fan does not run.

–

Refer to “Chart A”.

–

Refer to “Chart B”.