FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Inspection Procedure 3












CIRCUIT OPERATION
- The fan controller is powered from fusible link number 5.
- The ECM [M/T] or PCM [A/T] 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 [M/T] or PCM [A/T] activates the fan controller to drive the radiator fan motor and condenser fan motor.

TECHNICAL DESCRIPTION
- The cause could be a malfunction of the fan controller power supply or ground circuit.
- The cause could also be a malfunction of the fan controller or the ECM [M/T] or PCM [A/T].

TROUBLESHOOTING HINTS
- Malfunction of fusible link
- Malfunction of fan control relay
- Malfunction of fan controller
- Malfunction of ECM [M/T] or PCM [A/T]
- Damaged wiring harness or connector

DIAGNOSIS

Required Special Tool:
MB991223: Harness Set





STEP 1. Check the circuit at fan controller connector A-30.
1. Disconnect fan controller 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.
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-13X.
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 controller connector A-30.
Q: Are the harness wires between fan control relay connector A-13X and fan controller connector A-30 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 me 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 controller connector A-30.
1. Disconnect fan controller connector A-30, and measure at the harness side connector.
2. Measure the resistance between terminal number 1 and ground.
Q: Is me resistance less than 2 ohm?
YES: Go to Step 9.
NO: Go to Step 8.





STEP 8. Check the harness wire between fan controller connector A-30 and ground.
Q: Are the harness wires between fan controller 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-49 <2.4L-M/T>, C-51 <3.0L-M/T> or PCM connector C-50 <2.4L-A/T>, C- 52 <3.0L-A/T>.
1. Connect ECM connector C-49 <2.4L-M/T>, C-51 <3.0L-M/T> or PCM connector C-50 <2.4L-A/T>, C-52 <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-49 <2.4L-M/T>, C-51 <3.0L-M/T> or PCM connector C-50 <2.4L-A/T>, C-52 <3.0L-A/T> and fan controller connector A-30.

NOTE: If intermediate connector C-07 is damaged, repair or replace it.








Q: Are the harness wires between ECM connector C-49
<2.4L-M/T>, C-51 <3.0L-M/T> or PCM connector C-50
<2.4L-A/T>, C-52 <3.0L-A/T> and fan controller 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-49 <2.4L-M/T>, C-51 <3.0L-M/T>or PCM connector C-50 <2.4L-A/T>, C-52 <3.0L-A/T>.
1. Disconnect ECM connector C-49 <2.4L-M/T>, C-51 <3.0LM/T> or PCM connector C-50 <2.4L-A/T>, C-52 <3.0L-A/T>.
2. Pull out pin 21 <2.4L-M/T> or 18 <2.4L-A/T, 3.0L> to disconnect it.
3. Reconnect ECM connector C-49 <2.4L-M/T>, C-51 <3.0LM/T> or PCM connector C-50 <2.4L-A/T>, C-52 <3.0L-A/T> with pin 21 <2.4L-M/T> or 18 <2.4L-A/T, 3.0L> 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 [M/T] or PCM [A/T] 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.