3: Radiator Fan and Condenser Fan Do Not Operate
Inspection Procedure 3: Radiator fan and condenser fan do not operate
Radiator Fan and Condenser Drive Circuit
CIRCUIT OPERATION
^ The fan control module is powered from fusible link number 5.
^ The ECM or PCM judges the required revolution speed of radiator fan motor and condenser fan motor using the input signals transmitted from A/C switch, automatic compressor controller, vehicle speed sensor and engine coolant temperature sensor. The ECM
TECHNICAL DESCRIPTION
^ The cause could be a malfunction of the fan control module power supply or ground circuit.
^ The cause could also be a malfunction of the fan control module or the ECM
TROUBLESHOOTING HINTS
^ Malfunction of fusible link
^ Malfunction of fan control relay
^ Malfunction of fan control module
^ Malfunction of ECM
^ Damaged wiring harness or connector
DIAGNOSIS
Required Special Tool: MB991223: Harness Set
STEP 1. Check the circuit at fan control module connector A-30.
1. Disconnect fan control module connector A-30, and measure at the harness side connector.
2. Measure the voltage between terminal number 3 and ground.
^ When the ignition switch is turned to "ON" position, voltage should be battery positive voltage.
Q: Is the voltage battery positive voltage when the ignition switch is turned to "ON" position?
YES: Go to Step 7.
NO: Go to Step 2.
STEP 2. Check the fan control relay.
Refer to Fan Control Relay Continuity Check.
Q: Is the fan control relay in good condition?
YES: Go to Step 3.
NO: Replace it, then go to Step 10.
STEP 3. Check for continuity between fusible link number 5 and fan control relay connector A-1 3X.
Q: Are the harness wires between fusible link number 5 and fan control relay connector A-13X damaged?
YES: Repair or replace them, then go to Step 12.
NO: Go to Step 4.
STEP 4. Check for continuity between fan control relay connector A-13X and fan control module connector A-30.
Q: Are the harness wires between fan control relay connector A-13X and fan control module connector A30 damaged?
YES: Repair or replace them, then go to Step 12
NO: Go to Step 5.
STEP 5. Check for continuity between MFI relay connector A-21X and fan control relay connector A-13X.
Q: Are the harness wires between MFI relay connector A21X and fan control relay connector A-13X damaged?
YES: Repair or replace them, then go to Step 12.
NO: Go to Step 6.
STEP 6. Check for continuity between fan control relay connector A-13X and ground.
Q: Are the harness wires between fan control relay connector A-13X and ground damaged?
YES: Repair or replace them, then go to Step 12.
NO: There is no action to be taken.
STEP 7. Check the circuit at fan control module connector A-30.
1. Disconnect fan control module connector A-30, and measure at the harness side connector.
2. Measure the resistance between terminal number 1 and ground.
Q: Is the resistance less than 2 ohm?
YES: Go to Step 9.
NO: Go to Step 8.
STEP 8. Check the harness wire between fan control module connector A-30 and ground.
Q: Are the harness wires between fan control module connector A-30 and ground damaged?
YES: Repair or replace them, then go to Step 12.
NO: There is no action to be taken.
STEP 9. Check the circuit at ECM connector C-109 <2.4L M/T>, C-111 3.0L-M/T>or PCM connector C-110 <2.4L-A/T>, C-112 <3.0L-A/T>.
1. Connect ECM connector C-109 <2.4L-M/T>, C-111 <3.0LM/T> or PCM connector C-110 <2.4L-A/T>, C-112 <3.0L-A/ T>.
2. Start the engine and allow it to idle.
3. Measure the voltage between terminal number 21 <2.4L-M/ T> or 18 <2.4L-A/T, 3.0L> and ground.
Q: Is the voltage 0.7 volt or more when the radiator fan is operating?
YES: Go to Step 11.
NO: Go to Step 10.
STEP 10. Check the harness wire between ECM connector C-109 <2.4L-M/T>, C-111 <3.0L-M/T>or PCM connector C110 <2.4L-A/T>, C-112 <3.0L-A/T> and fan control module connector A-30.
NOTE: If intermediate connector C-06 is damaged, repair or replace it.
Q: Are the harness wires between ECM connector C-109, C-111 or PCM connector C-110, C-112 and fan control module connector A-30 damaged?
YES: Repair or replace them, then go to Step 12.
NO: Go to Step 11.
STEP 11. Check the fan control module at ECM connector C-109 , C-111 or PCM connector C-110 , C-112 .
1. Disconnect ECM connector C-109 , C-111 or PCM connector C-110 , C-112 .
2. Pull out pin 21 or 18 to disconnect it.
3. Reconnect ECM connector C-109 , C-111 or PCM connector C-110 , C-112 with pin 21 or 18 still removed.
4. Turn the ignition switch to "ON" position.
Q: Do the radiator fan motor and condenser fan motor operate?
YES: Replace the ECM or PCM. Then go to Step 12.
NO: Replace the radiator fan motor and fan control module assembly. Then go to Step 12.
STEP 12. Check the symptoms.
Q: Do the radiator fan and condenser fan operate correctly?
YES: This diagnosis is complete.
NO: Return to Step 1.