Acura TSX / Honda Accord CL. Manual - part 399

Fig. 1: Locating Cooling Fan Components
Courtesy of AMERICAN HONDA MOTOR CO., INC. 

TROUBLE SHOOTING 

SYMPTOM TROUBLE SHOOTING INDEX 

RADIATOR FAN CIRCUIT TROUBLE SHOOTING 

1. Check the No. 11 (20-amp) fuse in the under-hood fuse/relay box, and the No. 30 (7.5-amp) fuse in the 

under-dash fuse/relay box. If fuses are OK, go to next step. If fuses are not OK, replace the fuse(s) and 
recheck.  

2. Remove the radiator fan relay from the under-hood fuse/relay box, and test it. See FAN RELAYS under 

COMPONENT TESTS. If the relay is OK, go to next step. If relay is not OK, replace radiator fan relay.  

3. Measure the voltage between radiator fan relay 4-pin socket, terminal No. 2 and body ground. See Fig. 2 . 

Symptom

Perform Test

Engine overheats.

1. Inspect the water pump.  

2. Check for a broken drive belt.  

3. Check the drive belt auto-tensioner.  

4. Check the thermostat.  

5. Check for coolant leakage (from gaskets, 

hoses, O-rings, etc.).  

6. Check for dirt, leaves, or insects on 

radiator and condenser.  

7. Check for damaged or deformed fan 

shroud.  

8. Check for plugged or deteriorated radiator 

hoses.  

9. Check the radiator cap.  

10. Inspect the fan motors or fan relays.  

11. Check for plugged heater core or hose(s).  

12. Check the coolant level.  

13. Check for deteriorated coolant.  

14. Check for a damaged cylinder head gasket. 

Radiator fan does not run at all.

RADIATOR FAN CIRCUIT TROUBLE 

SHOOTING .

Radiator fan does not run for engine cooling, but it 
runs with A/C ON.

RADIATOR FAN SWITCH CIRCUIT 

TROUBLE SHOOTING (OPEN) .

Radiator fan runs with ignition switch ON, A/C OFF, 
and engine temperature below 199°F (93°C).

RADIATOR FAN SWITCH CIRCUIT 

TROUBLE SHOOTING (SHORT) .

Radiator fan does not run with the A/C ON, but it runs 
for engine cooling.

See TROUBLE SHOOTING in appropriate A/C-

HEATER SYSTEMS article.

 

2004 Acura TSX 

2004 ENGINE COOLING Electric Cooling Fans - TSX

  

 

If there is battery voltage, go to next step. If battery voltage is not present, replace the under-hood 
fuse/relay box.  

4. Connect radiator fan relay 4-pin socket, terminal No. 1 and No. 2 with a jumper wire. See Fig. 2 . If the 

radiator fan runs, go to next step. If radiator fan does not run, go to step 6 .  

5. Disconnect the jumper, and turn the ignition switch ON. Check for voltage between radiator fan relay 4-

pin socket, terminal No. 3 and body ground. See Fig. 2 . If there is battery voltage, go to step 8 . If battery 
voltage is not present, check for an open in the Black/Yellow wire between the under-hood fuse/relay box 
and under-dash fuse/relay box.  

6. Disconnect the radiator fan motor 2-pin connector. Check for continuity between radiator fan relay 4-pin 

socket, terminal No. 1 and radiator fan motor 2-pin connector, terminal No. 2. See Fig. 2 and Fig. 3 . If 
there is continuity, go to next step. If there is no continuity, repair open in the wire between the under-
hood fuse/relay box and radiator fan motor 2-pin connector, terminal No. 2.  

7. Check for continuity between radiator fan motor 2-pin connector, terminal No. 1 and body ground. See 

Fig. 3 . If there is continuity, replace the radiator fan motor. See COOLING FANS under REMOVAL & 
INSTALLATION. If there is no continuity, check for an open in the wire between radiator fan motor 2-
pin connector, terminal No. 1 and body ground. If the wire is OK, check for a poor ground at G301.  

8. Reinstall the radiator fan relay. Disconnect the radiator fan switch 2-pin connector. Connect radiator fan 

switch 2-pin connector, terminal No. 1 and No. 2 with a jumper wire. See Fig. 4 . If the radiator fan runs, 
replace the radiator fan switch. See RADIATOR FAN SWITCH under REMOVAL & 
INSTALLATION. If radiator fan does not run, go to next step.  

9. Remove the jumper wire, and measure the voltage between radiator fan switch 2-pin connector, terminal 

No. 2 and body ground. See Fig. 4 . If there is battery voltage, check for an open in the wire between 
radiator fan switch 2-pin connector, terminal No. 1 and body ground. If the wire is OK, check for a poor 
ground at G301. If battery voltage is not present, repair-open in the wire between radiator fan switch 2-
pin connector, terminal No. 2 and the under-hood fuse/relay box. 

 

2004 Acura TSX 

2004 ENGINE COOLING Electric Cooling Fans - TSX

  

 

Fig. 2: Identifying Radiator Fan Relay 4-pin Socket Terminals 
Courtesy of AMERICAN HONDA MOTOR CO., INC.

 

2004 Acura TSX 

2004 ENGINE COOLING Electric Cooling Fans - TSX

  

 

Fig. 3: Identifying Radiator Fan Motor 2-pin Connector Terminals 
Courtesy of AMERICAN HONDA MOTOR CO., INC. 

Fig. 4: Identifying Radiator Fan Switch 2-pin Connector Terminals

 

2004 Acura TSX 

2004 ENGINE COOLING Electric Cooling Fans - TSX