Inspection Procedure 4
INSPECTION PROCEDURE 4: Radiator Fan and Condenser Fan do not Change Speed or StopNOTE: If the engine coolant temperature reaches 110 °C (230°F) or higher, the radiator fan control runs the radiator fan for up to 5 minutes even after the ignition switch is turned to the "LOCK" (OFF) position [the fan stops its rotation when the engine coolant temperature decreases to 110°C (230°F) or lower.]
Part 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
TECHNICAL DESCRIPTION
^ The fan control module has variable control of the radiator fan motor and the condenser fan motor speeds using signals transmitted from the PCM.
TROUBLESHOOTING HINTS
^ Malfunction of fan control relay
^ Malfunction of fan control module
^ Malfunction of PCM
DIAGNOSIS
Required Special Tool:
^ MB991223: Harness Set
STEP 1. Check the fan control relay.
Q: Is the fan control relay in good condition?
YES: Go to Step 2.
NO: Replace the part, then go to Step 6.
STEP 2. Check the harness wire between fan control relay connector A-10X (terminal 2) and fan control module connector A-20 (terminal 3).
Q: Are the harness wire between fan control relay connector A-10X and fan control module connector A-20 damaged?
YES: Repair or replace the part, then go to Step 6.
NO: Go to Step 3.
STEP 3. Measure the output circuit voltage at PCM connector C-109 (terminal 17) by backprobing.
1) Do not disconnect PCM connector C-109.
2) Start the engine and run it at idle. [Engine coolant temperature: 80°C (176°F) or less]
3) Measure the voltage between terminal number 17 and ground by backprobing.
Q: Is the voltage 0 - 0.3 volt when the radiator fan is not operating?
YES: Go to Step 6.
NO: Go to Step 4.
STEP 4. Check the harness wire between PCM connector C-109 and fan control module connector A-20.
NOTE: If intermediate connector A-14 terminal 7 is damaged, repair or replace it.
Q: Are the harness wires between PCM connector C-109 and fan control module connector A-20 damaged?
YES: Repair or replace them, then go to Step 6.
NO: Go to Step 5.
STEP 5. Check the fan control module at PCM connector C-109.
1) Disconnect PCM connector C-109.
2) Pull out the pin 17 and connect it to the body ground.
3) Reconnect PCM connector C-109 with pin 17 still removed.
4) Turn the ignition switch to the " ON" position.
Q: Do the radiator fan motor and condenser fan motor stop?
YES: Replace the PCM. Then go to Step 6.
NO: Replace the fan control module. Then go to Step 6.
STEP 6. Check the symptoms.
Q: Do the radiator fan and condenser fan operate correctly?
YES: The procedure is complete.
NO: Return to Step 1.