Isuzu KB P190. Manual — part 30

1-86 HEATER AND AIR CONDITIONING

BLOWER MOTOR DOES NOT RUN

Replace

YES

• Is No.SBF-6 (30A) (except C24SE) or No.SBF-8
(30A) (C24SE) slow blow fuse OK?

• Is heater & A/C relay (X-11) OK?

YES

• Is resistor OK?

YES

• Is fan control knob (Fan switch) OK?

YES

YES

• Check to see if battery voltage is present at
chassis side connector terminal No.C105-1 is there a
battery voltage?

• Turn the ignition switch "ON" (Engine is running)

• Fan control knob (Fan switch) "ON"

• Is blower motor OK?

YES

Open circuit either between chassis side connector
terminal No.C105-2 and No.C104-3 or No.B13-1 and
body ground No.C-109.

NO

Replace

NO

Replace

NO

NO

Replace control lever
assembly

Replace

NO

NO

Open circuit between
No.SBF-6 (30A) (except
C24SE) or No.SBF-8 (30A)
(C24SE) slow blow fuse and
No.C105-1.

HEATER AND AIR CONDITIONING 1-87

BLOWER MOTOR DOES NOT RUN IN CERTAIN POSITION

A

1: (Low)

Blower motor does not

B

2: (Medium Low) Position

run at

C

3: (Medium Hi)

D

4: (High)

* Checking is performed only when in the malfunction

mode.

• Is resistor OK?

YES

• Is fan control knob (Fan switch) OK?

YES

Condition:

• Open circuit between chassis side connector

terminal No. C104-2 and No. B13-3

B

Condition :

• Open circuit between chassis side connector

terminal No. C104-4 and No. B13-6

C

Condition:

• Open circuit between chassis side connector

terminal No. C104-1 and No. B13-5

D

Condition:

• Open circuit between chassis side connector

terminal No. C105-2 and No. B13-4

Replace

NO

NO

Replace control lever
assembly

A

1-88 HEATER AND AIR CONDITIONING

BLOWER MOTOR DOES NOT STOP AT “OFF” POSITION

• Is fan control knob (Fan switch) OK?

YES

Check the circuit between chassis side connector terminals
for short to GND

• No. C105-2 and No. C104-3

(or)

• No . C105-2 and No. B13-4

(or)

• No . C104-1 and No. B13-5

(or)

• No . C104-4 and No. B13-6

(or)

• No . C104-2 and No. B13-3

NO

Replace control lever assembly

HEATER AND AIR CONDITIONING 1-89

AIR CONDITIONING CYCLE TROUBLESHOOTING

TROUBLE POSSIBLE

CAUSE

CORRECTION

1. Magnetic clutch does not run

•

Refer to “MAGNETIC CLUTCH”
troubleshooting in this section

2. Compressor is not rotating properly
•

Drive belt loosened or broken

•

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

•

Magnetic clutch face is not clean and
slips

•

Clean the magnetic clutch face or replace

•

Incorrect clearance between magnetic
drive plate and pulley

•

Adjust the clearance (Refer to
“COMPRESSOR OVERHAUL”)

•

Compressor oil leaks from shaft seal or
shell

•

Replace the compressor

•

Compressor seized

•

Replace the compressor

3. Insufficient or excessive charge of

refrigerant

•

Discharge and recover refrigerant.
Recharge to specified amount.

4. Leaks in the refrigerant system

•

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

5. Condenser clogged or insufficient radiation

•

Clean the condenser or replace as
necessary

•

Check radiator or condenser fan function

6. Temperature control link unit of the heater

unit defective

•

Repair the link unit

7. Unsteady operation due to foreign

substance in expansion valve

•

Replace the expansion valve

No cooling or
insufficient
cooling

8. Poor operation of electronic thermostat

•

Check electronic thermostat and replace
as necessary

1. Evaporator clogged or frosted

•

Check evaporator core and replace or
clean the core

2. Air leaking from cooling unit or air duct

•

Check evaporator and duct connection,
then repair as necessary

Insufficient
velocity
of cooling air

3. Blower motor does not rotate properly

•

Refer to “FAN CONTROL KNOB (FAN
SWITCH)” troubleshooting in this section

* For the execution of the charging and discharging operation in the table above, refer to the “RECOVERY,
RECYCLING, EVACUATING AND CHARGING” in this section.