1. Check the Easy Stuff First:
* Fuse: Check the fuse(s) related to the radiator fan in the fuse box (usually under the hood, but consult your owner's manual for the exact location and fuse diagram). There might be one for the fan itself and another for the fan relay. Replace any blown fuses.
* Relay: The relay is an electromagnetic switch that activates the fan. Locate the radiator fan relay (again, check your owner's manual). You can often swap it with a similar relay (often the horn relay is the same amperage) to see if the problem is with the relay itself. If the fan works with the swapped relay, replace the original radiator fan relay.
* Low Coolant: If the coolant level is low, the system may be designed to not turn the fan on to prevent damage. Check your coolant level and add coolant if necessary. *Never open a hot radiator cap.*
2. More Involved Troubleshooting:
* Fan Motor: If the fuse and relay are good, the fan motor itself could be faulty. You can test the fan motor directly by applying 12V power to its terminals (be cautious and use the correct polarity – reversed polarity can damage the motor). If it doesn't run, the motor needs replacement. This usually requires removal of the fan shroud.
* Fan Switch/Sensor: The radiator fan is controlled by a temperature sensor (often the coolant temperature sensor) or a dedicated fan switch. A faulty sensor won't signal the need for the fan to turn on. You'll likely need a multimeter to test the sensor's resistance against its specifications (found in a repair manual or online).
* Wiring and Connections: Inspect the wiring harness leading to the fan motor, relay, and sensor for any broken wires, loose connections, or corrosion. Repair or replace any damaged wiring.
* PCM (Powertrain Control Module): In some cases, a malfunctioning PCM can prevent the radiator fan from working. This is less likely but possible. Diagnosing a PCM issue usually requires specialized tools and expertise.
3. Seeking Professional Help:
If you're not comfortable with electrical troubleshooting or mechanical repairs, it's best to take your Jeep to a qualified mechanic. Diagnosing the problem correctly is crucial to avoid further damage and ensure proper repair.
Important Safety Note: Remember that the radiator and coolant system are hot when the engine is running. Allow the engine to cool completely before working on any components of the cooling system. Wear appropriate safety glasses and gloves.
