1. Check the obvious:
* Engine Temperature: Is the engine overheating? Check your temperature gauge. If it's high, the problem is serious and you need to address it *immediately* to prevent engine damage. Don't continue driving.
* Coolant Level: Low coolant means the system can't effectively dissipate heat, leading to overheating and potentially causing the fan to cycle on and off erratically or not at all (some systems require sufficient coolant level for fan operation). Check the coolant reservoir. If low, add coolant (the correct type for your engine – consult your owner's manual). If it's consistently low, you likely have a leak.
* Fuse/Relay: Check the fuse and relay for the cooling fan circuit in your fuse box (usually under the hood or in the passenger compartment). Refer to your owner's manual for the location and amperage rating. A blown fuse or a faulty relay will prevent the fan from working. Replace with the correct fuse/relay.
* Fan Motor: If the fuse and relay are okay, the fan motor itself might be faulty. You could try directly applying 12V power to the fan motor (carefully!) to see if it spins. If it doesn't, the motor is likely bad and needs replacement.
* Fan Clutch (if applicable): Some vehicles use a viscous fan clutch. If yours does, and the engine is running, you might be able to visually inspect if the fan spins freely by hand when the engine is off. If it's locked up or seized, it needs replacement. This is less likely on a 2001 Malibu but still possible.
2. Less Obvious Issues (require more investigation):
* Temperature Sensor: The engine's coolant temperature sensor tells the PCM (Powertrain Control Module) when to turn on the fan. A faulty sensor might not send the correct signal. A scan tool can check for sensor readings.
* Wiring: Check the wiring harness connected to the fan, the relay, and the temperature sensor for any damage, loose connections, or corrosion.
* PCM (Powertrain Control Module): In rare cases, a faulty PCM could be the culprit. This requires professional diagnosis.
* Ground Connection: A poor ground connection can prevent the fan from operating correctly.
3. Diagnosis:
* OBD-II Scan Tool: Using an OBD-II scanner can read diagnostic trouble codes (DTCs) from the PCM. This will help pinpoint the exact cause of the problem. Many auto parts stores offer free code reading.
Safety Precautions:
* Never work on a hot engine. Allow it to cool down completely before performing any checks or repairs.
* Always disconnect the negative battery terminal before working on any electrical components.
If you're not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic for diagnosis and repair. Ignoring a non-functional cooling fan, especially if the engine is overheating, can lead to serious and expensive engine damage.
