Inspection Procedure 4

INSPECTION PROCEDURE 4: Radiator Fan and Condenser Fan do not Change Speed or Stop

NOTE: 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.]

Radiator Fan and Condenser Fan Drive Circuit
Refer to Inspection Procedure 3.

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 fan controller has variable control of the radiator fan motor and the condenser fan motor speeds using signals transmitted from the ECM [M/T] or PCM [A/T].

TROUBLESHOOTING HINTS
- Malfunction of fan control relay
- Malfunction of fan controller
- Malfunction of ECM or PCM [A/T]

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-09X and fan controller connector A-30.
Q: Are the harness wire between fan control relay connector A-09X and fan controller connector A-30 damaged?
YES: Repair or replace the part, then go to Step 6.
NO: Go to Step 3.

STEP 3. 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>, C52 <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 run it at idle. [Engine coolant temperature: 80° C (176° F) or less]
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 - 0.3 volt when radiator fan is not operating?
YES: Go to Step 6.
NO: Go to Step 4

STEP 4. Check the harness wire between ECM connector C - 9 <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 6.
NO: Go to Step 5.

STEP 5. Check the fan controller 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 Cog <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. Pull out the terminal number <2.4L-M/T> or 18 <2.4L-A/T, 3.0L> and connect it to the body ground.
3. Reconnect ECM connector C49 <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> with pin 21 <2.4L-M/T> or 18 <2.4L-A/T, 3.0L> 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 ECM [M/T] or PCM [A/T]. Then go to Step 6.
NO: Replace the radiator fan motor and fan controller assembly. Then go to Step 6.

STEP 6. Check the symptoms.
Q: Do the radiator fan and condenser fan operate correctly?
YES: This diagnosis is complete.
NO: Return to Step 1.