2007 ISUZU KB P190 heater

HEATER AND AIR CONDITIONING 1-81
INSPECTION AND REPAIR



840R300005-X

Resistor
As for air-conditioning model, fixed on left (RHD) / right (LHD)
side of the evaporator unit.
As for heater only model, fixed on left (RHD) / right (LHD) side
of the duct placed between blower unit and heater unit.
Replace the resistor with a new on if the coil is found to be
open or if the resistance value deviates from the specified
range.




Terminal Resistance
3 – 2 2.04 Ω
3 – 4 0.88 Ω
3 – 1 0.31 Ω



Blower motor
Check blower motor for smooth rotation.
Connect the battery positive terminal to the No.1 terminal of the
blower motor and negative to the No.2.
Be sure to check to see if the blower motor operates correctly.


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ISUZU KB P190 2007

1-82 HEATER AND AIR CONDITIONING


RTW 710SH000801

Fan switch and A/C switch
Check for continuity between fan switch and A/C switch side
connector terminals.
(A/C (4JA1-T, 4JJ1-TC Standard Output, 4JJ1-TC High
Output, 4JK1-TC High Output))

B-13 B-57
Terminal No.
SW .
position
1234 5 6 2 3156
OFF

1
2
3
(FAN SW .)
4
OFF (A/C SW .)ON



RUW 710SH000501
(A/C (4JH1-TC, C24SE)).

B-13 B-57
Terminal
No.
SW .
position
123 4 5 6156
OFF
1
2
3
(FAN SW .)
4
OFF (A/C SW .)ON
D08R300070

(Cooler)

B-13 B-57
Terminal
No.
SW .
position
1 2 3 4 5 6 2 3 10 11
OFF
1
2
3
(FAN SW .)
4
OFF (A/C SW .)ON

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ISUZU KB P190 2007

HEATER AND AIR CONDITIONING 1-83


RTW 410SH000201

Electronic thermostat
Check for continuity between electronic thermostat side
connector terminals.
(A/C)


(Cooler)

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ISUZU KB P190 2007

1-84 HEATER AND AIR CONDITIONING



RTW 4A0SH000201

Triple Pressure switch
Disconnect pressure switch connector and check for continuity
between pressure switch side connector terminal.


825r300045


Heater and thermo switch relay.
Check for continuity between the relay terminals.
1 - 5 ⋅⋅⋅⋅⋅ No continuity
(W hen battery voltage is applied between 2 - 4 )
1 - 5 ⋅⋅⋅⋅⋅ Continuity
825r300023

Check for continuity between the relay terminals.
1 - 2 ⋅⋅⋅⋅⋅ No continuity
(W hen battery voltage is applied between 3 - 4 )
1 - 2 ⋅⋅⋅⋅⋅ Continuity




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ISUZU KB P190 2007

HEATER AND AIR CONDITIONING 1-85
TROUBLESHOOTING
FAN CONTROL KNOB (FAN SWITCH)
Current flows to the blower motor through the Heater & A/C relay (X-11) to activate the rotation of the blower motor
by turning “ON” the fan control knob (fan switch). Blower motor speed is controlled in stages by the resistor, by
operating the switch from “LOW ” to “HIGH.”



RTW 710LF004201

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ISUZU KB P190 2007

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.


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ISUZU KB P190 2007

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)
* Checkin
g is performed only when in the malfunction
mode.
•
Is resistor OK?
YES
•
Is fan control knob (Fan switch) OK?
YES
Condition:
•
O
pen circuit between chassis side connector
terminal No. C104-2 and No. B13-3
B Condition :
•
O
pen circuit between chassis side connector
terminal No. C104-4 and No. B13-6
C Condition:
•
O
pen circuit between chassis side connector
terminal No. C104-1 and No. B13-5
D Condition:
•
O
pen circuit between chassis side connector
terminal No. C105-2 and No. B13-4
Replace
NO
NO
Replace control leverassembly A


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ISUZU KB P190 2007

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



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ISUZU KB P190 2007