Inspection Procedure 3
INSPECTION PROCEDURE 3: Radiator Fan and Condenser Fan do not OperateRadiator Fan and Condenser Driver Circuit
2.4L ENGINE
Part 1 Of 2:
Part 2 Of 2:
[3.0L ENGINE]
CIRCUIT OPERATION
^ The fan controller is powered from fusible link number 2.
^ 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 (terminal number 3).
1. Disconnect fan controller connector A-30 (terminal number 3), 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 2 and fan control relay connector A-09X (terminal number 4).
Q: Are the harness wires between fusible link number 2 and fan control relay connector A-09X (terminal number 4) 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-09X (terminal number 2) and fan controller connector A-30 (terminal number 3).
Q: Are the harness wires between fan control relay connector A-09X (terminal number 2) and fan controller connector A-30 (terminal number 3) 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-1 8X (terminal number 4) and fan control relay connector A-09X (terminal number 1).
Q: Are the harness wires between MFI relay connector A-18X (terminal number 4) and fan control relay connector A-09X (terminal number 1) 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-09X (terminal number 3) and ground.
Q: Are the harness wires between fan control relay connector A-09X (terminal number 3) and ground damaged?
YES: Repair or replace them, then go to Step 12.
NO: Go to Step 7.
STEP 7. Check the circuit at fan controller connector A-30 (terminal number 1).
1. Disconnect fan controller connector A-30 (terminal number 1), 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 controller connector A-30 (terminal number 1) and ground.
Q: Are the harness wires between fan controller connector A-30 (terminal number 1) and ground damaged?
YES: Repair or replace them, then go to Step 12.
NO: Go to Step 9.
STEP 9. Check the circuit at ECM connector C-49 (terminal number 21) <2.4L-M/T>, C-51 (terminal number 18) <3.0L-M/T> or PCM connector C-50 (terminal number 18) <2.4L-A/T>, C-52 (terminal number 18) <3.0L-A/T>.
1. Connect ECM connector C-49 (terminal number 21) <2.4L-M/T>, C-51 (terminal number 18) <3.0L-M/T> or PCM connector C-50 (terminal number 18) <2.4L-A/T>, C-52 (terminal number 18) <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 (terminal number 21) <2.4L-M/T>, C-51 (terminal number 18) <3.0L-M/T> or PCM connector C-50 (terminal number 18) <2.4L-A/T>, C-52 (terminal number 18) <3.0L-A/T> and fan controller connector A-30 (terminal number 2).
NOTE: If intermediate connector C-07 (terminal number 6) is damaged, repair or replace it.
Q: Are the harness wires between ECM connector C-49 (terminal number 21) <2.4L-M/T>, C-51 (terminal number 18) <3.0L-M/T> or PCM connector C-50 (terminal number 18) <2.4L-A/T>, C-52 (terminal number 18) <3.0L-A/T> and fan controller connector A-30 (terminal number 2) 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 (terminal number 21) <2.4L-M/T>, C-51 (terminal number 18) <3.0L-M/T> or PCM connector C-50 (terminal number 18) <2.4L-A/T>, C-52 (terminal number 18) <3.0L-A/T>.
1. Disconnect ECM connector C-49 (terminal number 21) <2.4L-M/T>, C-51 (terminal number 18) <3.0L-M/T> or PCM connector C-50 (terminal number 18) <2.4L-A/T>, C-52 (terminal number 18) <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 (terminal number 21) <2.4L-M/T>, C-51 (terminal number 18) <3.0L-M/T> or PCM connector C-50 (terminal number 18) <2.4L-A/T>, C-52 (terminal number 18) <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.