Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 13

HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–23

Air Conditioning Parts

852R200008

Legend

(1) Liquid Line (High-Pressure Pipe)
(2) Clip
(3) Discharge Line (High-Pressure Hose)
(4) Pressure Switch
(5) Receiver/Drier

(6) Condenser Air Guide
(7) Condenser & Receiver Tank Assembly
(8) Condenser Fan
(9) Compressor

(10) Suction Line (Low-Pressure Hose)

(11) Evaporator Assembly

1A–24 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Diagnosis

Air Conditioning Cycle Diagnosis

Condition

Possible cause

Correction

No cooling or insufficient cooling.

Magnetic clutch does not run.

Refer to 

“Magnetic Clutch Diagnosis”

in this section.

Compressor is not rotating properly.
Drive belt is loose or broken.

Adjust the drive belt to the specified
tension or replace the drive belt.

Compressor is not rotating properly.
Magnetic clutch face is not clean and
slips.

Clean the magnetic clutch face or
replace.

Compressor is not rotating properly.
Incorrect clearance between
magnetic drive plate and pulley.

Adjust the clearance. Refer to
Compressor in this section.

Compressor is not rotating properly.
Compressor oil leaks from the shaft
seal or shell.

Replace the compressor

Compressor is not rotating properly.
Compressor is seized.

Replace the compressor

Insufficient or excessive charge of
refrigerant.

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

Leaks in the refrigerant system.

Check the refrigerant system for
leaks and repair as necessary.
Discharge and recover the
refrigerant.  Recharge to the
specified amount.

Condenser is clogged or insufficient
radiation.

Clean the condenser or replace as
necessary.

Temperature control link unit of the
heat unit is defective.

Repair the link unit.

Unsteady operation due to a foreign
substance in the expansion valve.

Replace the expansion valve.

Poor operation of the electronic
thermostat.

Check the electronic thermostat and
replace as necessary.

Insufficient velocity of cooling air.

Evaporator clogged or frosted.

Check the evaporator core and
replace or clean the core.

Air leaking from the cooling unit or air
duct.

Check the evaporator and duct
connection, then repair as
necessary.

Blower motor does not rotate
properly.

Refer to 

Fan Control Lever (Fan

Switch) Diagnosis in this section.

*For the execution of the charging and discharging
operation in the table above, refer to 

Recovery,

Recycling, Evacuating and Charging in this section.

HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–25

Checking The Refrigerant System With Manifold Gauge

Since Refrigerant-134a (HFC-134a) is used in the air
conditioning system in this vehicle, be sure to use
manifold gauges, charging hoses and other air
conditioning service tools for HFC-134a when
checking the refrigerant system.

Conditions:

D

Run the engine at idle

D

Air conditioning switch is “ON”

D

Run the blower motor at “HIGH” position (5 positions)

D

Temperature control set to “MAX COLD” (65

°

F)

D

Air source selector at “CIRC”

D

Open the engine hood

D

Close all the doors

Normal Pressure:

D

At ambient temperature: approx. 25–30

°

C

(77–86

°

F).

D

At low-pressure side: approx. 147.1–294.2 kPa
(21.3–42.7 psi).

D

At high-pressure side: approx. 1372.9–1863.3 kPa
(199.1–270.2 psi).

Refer to the table on the refrigerant pressure-temperature
relationship.

HFC-134a Pressure-Temperature Relationship

Pressure

Temperature

(kPa)

(psi)

(

°

C)

(

°

F)

36

5.3

–20

–4.4

67

9.7

–15

5

104

15

–10

14

147

21

–5

23

196

28

0

32

255

37

5

41

314

45

10

50

392

57

15

59

471

68

20

68

569

82

25

77

677

98

30

86

785

114

35

95

912

132

40

104

1059

154

45

113

1216

176

50

122

1A–26 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Connect The Manifold Gauge
Low-pressure hose (LOW) — Suction side
High pressure hose (HI) — Discharge side

901R100020

Legend

(1) Low Side
(2) High Side