Radiator and A/C Condenser Fan Low 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 PGM-FI DTCs (see GENERAL TROUBLESHOOTING INFORMATION ).

Check the No. 3-6 (MAIN FAN MTR) (30 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?

YES -Go to step 2.

NO -Replace the fuse, and recheck. If the fuse blow again, check for a short in the No. 3-6 (MAIN FAN MTR) (30 A) fuse circuit.
Connect the HDS to the DLC.
Start the engine.
Turn on the A/C.
Check the FAN LOW CTRL in the PGM-FI Data List with the HDS.
Is the FAN LOW CTRL on?

YES -Go to step 6.

NO -Substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), and recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).
Turn the ignition switch to LOCK (0).
Remove the radiator fan relay from the under-hood fuse/relay box, and test it (see POWER RELAY TEST ).
Is the relay OK?

YES -Go to step 8.

NO -Replace the radiator fan relay.
Measure the voltage between radiator fan relay 4P socket terminal No. 1 and body ground.

Fig 1: Measuring Voltage Between Radiator Fan Relay 4P Socket Terminal No. 1 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 9.

NO -Replace the under-hood fuse/relay box (see REMOVAL AND INSTALLATION ).
Connect radiator fan relay 4P socket terminals No. 1 and No. 2 with a jumper wire.

Fig 2: Connecting Radiator Fan Relay 4P Socket Terminals No. 1 And No. 2 Using Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Do the radiator and A/C condenser fans run on low?

YES -Go to step 10.

NO -Go to step 19.
Disconnect the jumper wire.
Turn the ignition switch to ON (II).
Measure the voltage between radiator fan relay 4P socket terminal No. 4 and body ground.

Fig 3: Measuring Voltage Between Radiator Fan Relay 4P Socket Terminal No. 4 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 13.

NO -Go to step 35.
Turn the ignition switch to LOCK (0).
Reinstall the radiator fan relay.
Jump the SCS line with the HDS.
NOTE: This step must be done to protect the ECM/PCM from damage.
Disconnect ECM/PCM connector A (49P).
Connect ECM/PCM connector A (49P) terminal No. 5 to body ground with a jumper.

Fig 4: Connecting ECM/PCM Connector A (49P) Terminal No. 5 To Body Ground Using Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to ON (II).
Do the A/C condenser and radiator fans run on low?

YES -Check for a loose wire or poor connection at ECM/PCM connector A (49P) terminal No. 5. If the connection is good, substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), and recheck. If the symptom/indication goes away, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).

NO -Repair an open in the wire between the radiator fan relay and the ECM/PCM.
Disconnect the jumper wire.
Reinstall the radiator fan relay.
Disconnect the radiator fan motor 2P connector.
Turn the ignition switch to ON (II), then turn on the A/C.
Measure the voltage between radiator fan motor 2P connector terminal No. 2 and body ground.

Fig 5: Measuring Voltage Between Radiator Fan Motor 2P Connector Terminal No. 2 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 24.

NO -Repair an open in the wire between the radiator fan relay and the radiator fan motor.
Turn off the A/C, then turn the ignition switch to LOCK (O).
Test the radiator fan motor.
Is the radiator fan motor OK?

YES -Go to step 26.

NO -Replace the radiator fan motor (see CONNECTING PIPE REPLACEMENT ).
Disconnect under-hood fuse/relay box connector B (14P).
Check for continuity between under-hood fuse/relay box connector B (14P) terminal No. 11 and radiator fan motor 2P connector terminal No. 1.

Fig 6: Checking Continuity Between Under-Hood Fuse/Relay Box Connector B (14P) Terminal No. 11 And Radiator Fan Motor 2P Connector Terminal No. 1
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 28.

NO -Repair an open in the wire between the under-hood fuse/relay box and the radiator fan motor.
Reconnect under-hood fuse/relay box connector B (14P) and the radiator fan motor 2P connector.
Remove the relay circuit board (see REMOVAL AND INSTALLATION ) from the under-hood fuse/relay box, and test the fan control relay (see FIVE-TERMINAL TYPE ).
Is the relay OK?

YES -Go to step 30.

NO -Replace the relay circuit board.
Reinstall the relay circuit board.
Disconnect the A/C condenser fan motor 2P connector.
Turn the ignition switch to ON (II), then set the A/C button and fan control button ON.
Measure the voltage between the A/C condenser fan motor 2P connector terminal No. 2 and body ground.

Fig 7: Measuring Voltage Between A/C Condenser Fan Motor 2P Connector Terminal No. 2 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 34.

NO -Repair an open in the wire between the under-hood fuse/relay box and the A/C condenser fan motor.
Check for continuity between the A/C condenser fan motor 2P connector terminal No. 1 and body ground.

Fig 8: Checking Continuity Between A/C Condenser Fan Motor 2P Connector Terminal No. 1 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Replace the A/C condenser fan motor (see CONNECTING PIPE REPLACEMENT ).

NO -Check for an open in the wire between the A/C condenser fan motor and body ground. If the wire is OK, check for poor ground at G301 (see LEFT ENGINE COMPARTMENT WIRE HARNESS (ENGINE COMPARTMENT BRANCH) ).
Measure the voltage between under-hood fuse/relay box connector B (14P) terminal No. 10 and body ground.

Fig 9: Measuring Voltage Between Under-Hood Fuse/Relay Box Connector B (14P) Terminal No. 10 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Repair an open in the wire between under-hood fuse/relay box connector B (14P) terminal No. 10 and the radiator fan relay socket.

NO -Replace the relay circuit board (see REMOVAL AND INSTALLATION ).