Cooling Fan Inoperative
Cooling Fan Inoperative (1.8L RPO-LAY)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
Circuit/System Description
The fan 1 relay provides power to the fan control module. The fan control module completes the fan motor circuit by providing a path to ground. The module energizes the fan and controls fan speed according to instructions received from the powertrain control module (PCM).
Diagnostic Aids
* The fan relay electrical contacts may be pitted or sticking. Replace the relay, if tapping gently on the relay, or wiggling the relay causes a change in the relays operation.
* The performance of the cooling relay may be affected by temperature. Check the relay after sitting outside overnight and after running the engine 30 minutes.
Use the following relay cavity table in order to locate the correct cavities to probe during diagnosis. The table layout corresponds to the cavity layout of the relay block.
Reference Information
Schematic Reference
Engine Cooling Schematics (Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Verify the HVAC system operates correctly.
• If an HVAC system condition is found, repair the HVAC condition first. Refer to Symptoms - HVAC Systems - Manual (Symptoms - HVAC Systems - Manual).
2. Ignition ON, command the cooling fan ON and OFF with a scan tool. Verify that the fan turns ON and OFF when changing between the commanded states.
Circuit/System Testing
1. Ignition OFF, disconnect the PCM connector X1.
2. Ignition ON, verify the cooling fan turns ON.
• If the fan is ON, replace the PCM.
• If the fan is OFF, test the PCM fan control circuit for a short to ground.
3. Ignition OFF, remove the cooling fan 1 relay.
4. Ignition ON, verify that a test lamp illuminates between the relay coil ignition circuit terminal 1 and ground.
• If the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance.
5. Connect a test lamp between the relay coil control circuit terminal 2 and the relay coil ignition circuit terminal 1. Verify the test lamp illuminates.
• If the test lamp does not illuminate, repair the open/high resistance in the relay coil control circuit.
6. Verify the test lamp illuminates between the relay switch B+ circuit terminal 3 and ground.
• If the test lamp does not illuminate, test the relay switch B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the RDI FAN fuse is open, test the relay controlled output circuit terminal 5 for a short to ground. If the circuit tests normal, test or replace the relay.
7. Ignition OFF, disconnect the fan control module (FCM).
8. Connect a 20A fused jumper between the relay switch B+ circuit terminal 3 and the relay controlled output circuit terminal 5 of the fan 1 relay.
9. Ignition ON, connect a test lamp to the FCM harness connector terminal 1. Verify the test lamp illuminates.
• If the test lamp does not illuminate, test the relay controlled output circuit for an open/high resistance.
10. Ignition OFF, disconnect the cooling fan electrical connector.
11. Connect a 30A fused jumper between B+ and the cooling fan terminal 2.
12. Connect a 30A fused jumper between ground and the cooling fan terminal 1. Verify the fan turns ON.
• If the fan is ON, test the FCM ground circuit terminal 3 for an open/high resistance. If the circuit tests normal, replace the FCM.
• If the fan is OFF, test the cooling fan motor circuits for an open/high resistance. If the circuit tests normal, replace the cooling fan.
Component Testing
1. Ignition OFF, disconnect the relay.
2. Test for 85-120 ohms at 20°C (68°F) between terminals 1 and 2.
• If the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals:
* 5 and 1
* 5 and 2
* 5 and 3
* 1 and 3
* 2 and 3
• If not the specified range, replace the relay.
4. Install a 20A fused jumper wire between relay terminal 1 and 12 volts. Install a jumper wire between relay terminal 2 and ground. Test for less than 2 ohms between terminals 3 and 5.
• If greater than the specified range, replace the relay.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Engine Coolant Fan Replacement (2.4L) (Service and Repair)Engine Coolant Fan Replacement (1.8L) (Service and Repair)
* Fan Control Module Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for control module replacement, setup, and programming