Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 14

 

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Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 14

 

 

HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–27

Condition

Possible cause

Correction

Discharge (High Gauge) Pressure
Abnormally High

Condenser clogged or dirty.

Clean the condenser fins

Abnormally High

Cooling fan does not operate
properly.

Check the cooling fan operation.

Discharge (High Gauge) Pressure
Abnormally High.
Insufficient cooling.

Excessive refrigerant in system.

Discharge and recover refrigerant.
Recharge to specified amount.

Discharge (High Gauge) Pressure
Abnormally High.
High pressure gauge drop. (After
stopping A/C, the pressure drops
approx. 196 kPa (28 psi) quickly)

Air in system.

Evacuate and charge refrigerant
system.

Discharge (High Gauge) Pressure
Abnormally Low.
Insufficient cooling

Insufficient refrigerant in system.

Check for leaks. Discharge and
recover the refrigerant. Recharge to
the specified amount.

Discharge (High Gauge) Pressure
Abnormally Low.
Low pressure gauge indicates
vacuum.

Clogged or defective expansion
valve.

Replace the expansion valve.

Discharge (High Gauge) Pressure
Abnormally Low.
Frost or dew on refrigerant line
before and after the receiver/drier or
expansion valve, and low pressure
gauge indicates vacuum.

Restriction caused by debris or
moisture in the receiver/drier.

Check system for restriction and
replace the receiver/drier.

Discharge (High Gauge) Pressure
Abnormally Low.

Compressor seal defective

Repair or replace the compressor.

High and low pressure gauge
balanced quickly. (After turned off
A/C)

Poor compression due to a defective
compressor gasket.

Repair or replace the compressor.

Suction (Low Gauge) Pressure
Abnormally High.
Low pressure gauge (Low pressure
gauge is lowered after condenser is
cooled by water.)

Excessive refrigerant in system.

Discharge and recover refrigerant
Recharge to specified amount.

Suction (Low Gauge) Pressure
Abnormally High.
Low pressure hose temperature.
(Low pressure hose temperature
around the compressor refrigerant

Unsatisfactory valve operation due
to  defective temperature sensor of
expansion valve.

Replace the expansion valve.

around  the  com ressor  refrigerant
line connector is lower than around
evaporator.)

Expansion valve opens too long.

Replace the expansion valve.

Suction (Low Gauge) Pressure
Abnormally High.
High and low pressure gauge
balanced quickly. (After turned off
A/C)

Compressor gasket is defective.

Repair or replace the compressor.

Suction (Low Gauge) Pressure
Abnormally Low.
Insufficient cooling.

Insufficient refrigerant in system.

Check for leaks. Discharge and
recover the refrigerant. Recharge to
specified amount.

Suction (Low Gauge) Pressure
Abnormally Low.
Frost on the expansion valve inlet
line

Expansion valve clogged.

Replace the expansion valve.

1A–28 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Condition

Correction

Possible cause

Suction (Low Gauge) Pressure
Abnormally Low
Receiver/drier inlet and outlet
refrigerant line temperature. (A
distinct difference in temperature
develops.)

Receiver/Drier clogged.

Replace the receiver/drier.

Suction (Low Gauge) Pressure
Abnormally Low.
Expansion valve outlet refrigerant
line. (Not cold and low pressure
gauge indicates vacuum.)

Expansion valve temperature sensor
is defective.

Replace the expansion valve.

Suction (Low Gauge) Pressure
Abnormally Low.
When the refrigerant line is clogged
or blocked, the low pressure gauge
reading will decrease, or a vacuum
reading may be shown.

Clogged or blocked refrigerant line.

Replace refrigerant line.

Suction (Low Gauge) Pressure
Abnormally Low.
Evaporator core is frozen.

Thermo switch defective.

Replace thermo switch.

Suction (Low Gauge) and Discharge
(High Gauge) Pressure Abnormally
High.

Excessive refrigerant in system.

Discharge and recover the
refrigerant, the Recharge to the
specified amount.

Insufficient cooling.

Condenser clogged or dirty.

Clean the condenser fin.

Suction (Low Gauge) and Discharge
(High Gauge) Pressure Abnormally
High.
Suction (Low) pressure hose (Not
cold).

Air in system.

Evacuate and charge refrigerant.

Suction (Low Gauge) and Discharge
(High Gauge) Pressure Abnormally
Low.
Insufficient cooling

Insufficient refrigerant in system.

Check for leaks. Discharge and
recover refrigerant. Recharge to
specified amount.

A/C — Air Conditioning

HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–29

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.

D08R200041

Condition

Possible cause

Correction

Condenser fan does not run.

–

Refer to “Chart A”.

–

Refer to “Chart B”.

1A–30 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Chart “A” Condenser Fan Does Not Run 

Step

Action

Yes

No

1

Are 30A fuse normal?

Go to 

Step 2

Replace

2

Is relay (X-16) normal?

Go to 

Step 3

Replace

3

Is pressure switch normal?

Go to 

Step 4

Switch defective

or insufficient

refrigerant.

4

Is fan motor normal?

Go to 

Step 5

Replace

5

1. Disconnect condenser fan relay (X-16).
2. Check to see if battery voltage is present at the chassis side

relay terminal NO. X16-5.

Is there a battery voltage?

Go to 

Step 6

Repair open

circuit between

Condenser Fan

fuse (30A) and

No.X16-5.

6

1. Reconnect condenser fan relay (X-16).
2. Check to see if battery voltage is present at chassis side

connector terminal No.C21-3.

Is there a battery voltage?

Go to 

Step 7

Repair open

circuit between

fuse (10A) and

C21-3.

7

Check to see if continuity between chassis side relay terminal
No.X16-2 and the chassis side connector terminal No.C21-4.

Is there a continuity?

Go to 

Step 8

Repair open

circuit.

8

Check to see if continuity between chassis side connector
terminal No. C16-1 and chassis side relay terminal No.X16-1.

Is there a continuity?

Poor ground or

open circuit

between chassis

side connector

terminal

No.X16-4 (or

No.C16-2) and

body ground

(No.C10).

Repair open

circuit.

Chart “B” Condenser Fan Does Not Stop 

Step

Action

Yes

No

1

1. Disconnect the triple pressure connector.

Does condenser fan stop?

Replace the triple

pressure switch.

Replace the

condenser fan

relay.

 

 

 

 

 

 

 

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