Inspection Procedure 3
INSPECTION PROCEDURE 3: Radiator Fan and Condenser Fan do not OperatePart 1 Of 2:
Part 2 Of 2:
CIRCUIT OPERATION
^ The fan control module is powered from fusible link number 2.
^ The 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 PCM activates the fan control module to drive the radiator fan motor and condenser fan motor.
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 PCM.
TROUBLESHOOTING HINTS
^ Malfunction of fusible link
^ Malfunction of fan control relay
^ Malfunction of MFI relay
^ Malfunction of radiator fan motor
^ Malfunction of condenser fan motor
^ Malfunction of fan control module
^ Malfunction of PCM
^ Damaged wiring harness or connector
DIAGNOSIS
Required Special Tool:
^ MB991223: Harness Set
STEP 1. Check the circuit at fan control module connector A-18 (terminal 3).
1. Disconnect fan control module connector A-18, and measure at the harness side connector.
2. Measure the voltage between terminal number 3 and ground.
^ When the ignition switch is turned to the "ON" position, voltage should measure battery positive voltage.
Q: Is there voltage battery positive voltage when the ignition switch is turned to the "ON" position?
YES: Go to Step 8.
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 1.
STEP 3. Check the MFI relay.
Q: Is the MFI relay in good condition?
YES: Go to Step 4.
NO: Replace it, then go to Step 1.
STEP 4. Check for harness damage between fusible link number 2 and fan control relay connector A-09X (terminal 4).
Q: Are the harness wires between fusible link number 2 and fan control relay connector A-09X damaged?
YES: Repair or replace them, then go to Step 13.
NO: Go to Step 5.
STEP 5. Check for harness damage between fan control relay connector A-09X (terminal 2) and fan control module connector A-18 (terminal 3).
Q: Are the harness wires between fan control relay connector A-09X (terminal 2) and fan control module connector A-18 (terminal 3) damaged?
YES: Repair or replace them, then go to Step 13.
NO: Go to Step 6.
STEP 6. Check for harness damage between MFI relay connector B-16X and fan control relay connector A-09X.
NOTE: After inspecting intermediate connector A-13 terminal 8 and joint connector C-103 terminal 28, 33 inspect the wires. If intermediate connector A-13 and joint connector C-103 are damaged, repair or replace them.
Q: Are the harness wires between MFI relay connector B-16X (terminal 4) and fan control relay connector A-09X (terminal 1) damaged?
YES: Repair or replace them, then go to Step 13.
NO: Go to Step 7.
STEP 7. Check for harness damage between fan control relay connector A-09X (terminal 3) and ground.
Q: Are the harness wires between fan control relay connector A-09X (terminal 3) and ground damaged?
YES: Repair or replace them, then go to Step 13.
NO: Go to Step 8.
STEP 8. Check the circuit at fan control module connector A-18 (terminal 1).
1. Disconnect fan control module connector A-18, and measure at the harness side connector.
2. Measure the resistance between terminal number 1 and ground.
Q: Is the resistance less than 2 ohms?
YES: Go to Step 10.
NO: Go to Step 9.
STEP 9. Check the harness wire between fan control module connector A-18 and ground.
Q: Are the harness wires between fan control module connector A-18 and ground damaged?
YES: Repair or replace them, then go to Step 13.
NO: Go to Step 10.
STEP 10. Measure the output circuit voltage at PCM connector C-114 (terminal 17) by backprobing.
1. Do not disconnect PCM connector C-114.
2. Start the engine and allow it to idle.
3. Measure the voltage between terminal number 17 and ground by backprobing.
Q: Is the voltage 0.7 volt or more when the radiator fan is operating?
YES: Go to Step 12.
NO: Go to Step 11.
STEP 11. Check the harness wire between PCM connector C-114 and fan control module connector A-18.
NOTE: If intermediate connector A-13 terminal 1 is damaged, repair or replace it.
Q: Are the harness wires between PCM connector C-114 (terminal 17) and fan control module connector A-18 (terminal 2) damaged?
YES: Repair or replace them, then go to Step 13.
NO: Go to Step 12.
STEP 12. Check the fan control module at PCM connector C-114.
1. Disconnect PCM connector C- 114.
2. Turn the ignition switch to the "ON" position.
Q: Do the radiator fan motor and condenser fan motor operate?
YES: Replace the PCM. Then go to Step 13.
NO: Replace the fan control module. Then go to Step 13.
STEP 13. Check the symptoms.
Q: Do the radiator fan and condenser fan operate correctly?
YES: The procedure is complete.
NO: Return to Step 1.