Isuzu KB P190. Service manual - part 37

1-114  HEATER AND AIR CONDITIONING 

C24SE 

 

 

 

 

RTW610XF000501 

HEATER AND AIR CONDITIONING  1-115 

MAGNETIC CLUTCH DOES NOT RUN (C24SE) 

 

Replace 

YES 

• Are the A/C thermo (X-15), heater & A/C (X-11) 
and A/C compressor (X-14) relay OK? 

• Are the No. SBF 8 fuse (30A) and the No. EB-13 
(10A) fuses OK? 

YES 

• Is the pressure switch (C-24) OK? 

YES 

• Are the A/C switch (B-57) and the fan switch (B-13) 
OK? 

NO 

YES 

• Is there continuity between the engine harness 
connector terminal No.1 (E-2) and the engine room 
harness connector terminal No.2 (X-14)? 

• Disconnect the A/C compressor relay. 

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

• A/C switch and fan control knob (fan switch "ON") 

NO

Replace 

NO

Defective switch or insufficient 
refrigerant 

NO

NO

Does the magnetic clutch 
operate? 

YES

Replace 

• Disconnect the magnetic clutch connector. 

• Is there battery voltage between the engine room 
harness connector terminal No.1 (E-2) and ground? 

Defective compressor 

YES

NO

Defective magnetic clutch  

• Is the electronic thermostat (C-55) OK? 

Replace 

NO

YES 

 

1-116  HEATER AND AIR CONDITIONING 

 

 

Open circuit between the No. EB-13 
fuse and the engine room harness 
connector terminal No.1 (X-14). 

NO

YES 

• Is there battery voltage between the engine room 
harness connector terminal No.1 (X-14) and 
ground? 

YES 

• Disconnect the A/C thermo relay. 

YES 

• Is there continuity between the ECM harness 
connector terminal C24SE No. 14 (C-56) and the 
engine room harness connector terminal No.4 
(X-14)? 

Open circuit between the No. EB-13 
fuse and the engine room harness 
connector terminal No. 3 (X-14). 

NO

• Is there battery voltage the engine room harness 
connector terminal No.3 (X-14) and ground? 

YES 

• Is there continuity between the ECM harness 
connector terminal C24SE No. 26 (C-56) and the 
engine room harness connector terminal No. 1 
(X-15)? 

Open circuit between the ECM 
harness connector terminal C24SE 
No.14 (C-56) and the engine room 
harness connector terminal No. 4 (X-
14). 

NO

YES 

• Is there battery voltage between the engine room 
harness connector terminal No. 2 (X-15) and 
ground? 

Open circuit between the ECM 
harness connector terminal C24SE 
No. 26 (C-56) and the engine room 
harness connector terminal No. 1 (X-
15). 

NO

YES 

• Is there continuity between the engine room 
harness connector terminal No. 3 (X-15) and the 
engine room harness connector terminal No. 1 (C-
24). 

Open circuit between the No. EB-13 
fuse and engine room harness 
connector terminal No. 2 (X-15). 

NO

• Disconnect the ECM harness connector. 

• Disconnect the pressure switch? 

Open circuit between the engine harness 
connector terminal No.1 (E-2) and the 
engine room harness connector terminal 
No.2 (X-14). 

NO 

 

HEATER AND AIR CONDITIONING  1-117 

 

 

YES 

• Disconnect the condenser fan relay connector condenser 
fan. 

YES 

• Is there battery voltage between the engine room 
harness connector terminal  NO. 3 (C-24) and ground?

Open circuit between the condenser fan 
relay No.3 (X-10) and engine room harness 
connector terminal No. 4 (C-24). 

NO 

• Is there continuity between the relay terminal No. 3 (X-
10) and engine  room harness connector terminal No.4 
(C-24)? 

YES 

Open circuit between the No. EB-13 fuse 
and engine room harness connector 
terminal No. 3 (C-24). 

NO

YES 

• Is there continuity between the engine room harness 
connector terminal No. 2 (C-55) and the engine room 
harness connector terminal No. 2 (C-24)? 

Open circuit between the engine room 
harness connector terminal No. 4 (X-15) 
and the engine room harness connector 
terminal No. 1 (C-24). 

NO

• Disconnect the pressure switch. 

• Is there continuity between the engine room harness 
connector terminal No. 4 (X-15) and the engine room 
harness connector terminal No. 1 (C-24). 

Open circuit between the No. EB-13 fuse 
and the engine room harness connector 
terminal No. 2 (X-15). 

NO

• Connect the A/C thermo relay connector. 

• Disconnect the electronic thermostat. 

Open circuit between the engine room 
harness connector terminal No.3 (X-15) 
and the engine room harness connector 
terminal No. 1 (C-24). 

NO