Radiator Fan High Speed Circuit Troubleshooting

NOTE:

Do not use this troubleshooting procedure if the A/C compressor is inoperative. Refer to the SYMPTOM TROUBLESHOOTING INDEX .
Before doing symptom troubleshooting, check for powertrain DTCs (see GENERAL TROUBLESHOOTING INFORMATION ).

Check the No. B30 (30 A) fuse in the under-dash fuse/relay box, and the No. B10 (7.5 A) fuse in the under-dash fuse/relay box.
Are the fuses OK?

YES -Go to step 2.

NO -Replace the fuse. If the fuse(s) continues to blow, locate and repair the short in the circuit between the under-dash fuse/relay box and radiator fan motor.
Remove the radiator fan relay from auxiliary under-hood relay box B and the fan control relay from auxiliary under-hood relay box A, and test the (see POWER RELAY TEST ).
Are the relays OK?

YES -Go to step 3.

NO -Replace the radiator fan relay and/or the fan control relay.
Check the radiator fan motor (see FAN MOTOR TEST ).
Is the fan motor OK?

YES -Go to step 4.

NO -Replace the radiator fan motor (see FAN, FAN MOTOR, AND SHROUD REMOVAL AND INSTALLATION ).
Measure the voltage between radiator fan relay socket terminal No. 1 and body ground.

Fig 1: Measuring Voltage Between Radiator Fan Relay Socket Terminal No. 1 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 5.

NO -Repair an open in the wire between radiator fan relay socket terminal No. 1 and under-dash fuse/relay box connector terminal B34. If the wire is OK, replace auxiliary under-hood relay box B.
Turn the ignition switch to ON (II).
Measure the voltage between radiator fan relay socket terminal No. 7 and body ground.

Fig 2: Measuring Voltage Between Radiator Fan Relay Socket Terminal No. 7 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 7.

NO -Repair an open in the wire between radiator fan relay socket terminal No. 7 and under-dash fuse/relay box B1. Check the A/C diode B. If the wire and A/C diode B is OK, replace auxiliary under-hood relay box B.
Measure the voltage between fan control relay socket terminal No. 13 and body ground.

Fig 3: Measuring Voltage Between Fan Control Relay Socket Terminal No. 13 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 8.

NO -Repair an open in the wire between auxiliary under-hood relay box A fan control relay socket terminal No. 13 and auxiliary under-hood relay box B A/C diode B socket terminal No. 13. If the wire is OK, replace auxiliary under-hood relay box A.
Turn the ignition switch to LOCK (0).
Disconnect the radiator fan motor 2P connector.
Measure the continuity between radiator fan relay socket terminal No. 2 and radiator fan motor 2P connector terminal No. 1.

Fig 4: Measuring Continuity Between Radiator Fan Relay Socket Terminal 2 And Radiator Fan Motor Connector Terminal 1
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to the step 11.

NO -Repair an open in the wire between radiator fan relay socket terminal No. 2 and the radiator fan motor 2P connector terminal No. 1.
Measure the continuity between fan control relay socket terminal No. 6 and radiator fan motor 2P connector terminal No. 2.

Fig 5: Measuring Continuity Between Fan Control Relay Socket Terminal 6 And Radiator Fan Motor Connector Terminal 2
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to the step 12.

NO -Repair an open in the wire between fan control relay socket terminal No. 6 and radiator fan motor 2P connector terminal No. 2.
Measure the continuity between fan control relay socket terminal No. 5 and body ground G401.

Fig 6: Measuring Continuity Between Fan Control Relay Socket Terminal No. 5 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to the step 13.

NO -Repair an open in the wire between fan control relay socket terminal No. 5 and body ground G401.
Connect the HDS to the DLC (see step 2 on GENERAL TROUBLESHOOTING INFORMATION ).
Turn the ignition switch to ON (II).
Make sure the HDS communicates with the vehicle and the ECM/PCM. If it does not communicate, troubleshoot the DLC circuit (see DLC CIRCUIT TROUBLESHOOTING ).
Jump the SCS line with the HDS, then turn the ignition switch to LOCK (0).
NOTE: This step must be done to protect the ECM/PCM from damage.
Disconnect ECM/PCM connector A (44P).
Measure the continuity between radiator fan relay socket terminal No. 8 and ECM/PCM connector terminal No. A4.

Fig 7: Measuring Continuity Between Radiator Fan Relay Socket Terminal 8 And ECM/PCM Connector Terminal A4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to the step 19.

NO -Repair an open in the wire between radiator fan relay socket terminal No. 8 and ECM/PCM connector terminal No. A4.
Measure the continuity between fan control relay socket terminal No. 15 and ECM/PCM connector terminal No. A5.

Fig 8: Measuring Continuity Between Fan Control Relay Socket Terminal 15 And ECM/PCM Connector Terminal A5
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Update the ECM/PCM (see ELD REPLACEMENT ) if it does not have the latest software, or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then recheck. If the symptom goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).

NO -Repair an open in the wire between fan control relay socket terminal No. 15 and ECM/PCM connector terminal No. A5.