Common Issues You May Encounter with the Jeep Wrangler Fan Blade
The radiator itself is not enough to keep your vehicle's engine at a normal temperature. Behind it mounts the Jeep Wrangler fan blade, which helps cool the component. However, it does not work the moment you start up your vehicle. It has to wait until the engine reaches the normal operating temperature of 195 to 215 F before it cycles on and off as needed to maintain the cool temperature. When the fan blade stops working, your car will most likely overheat. When you have noticed that the fan has stopped working, there should be a root cause to this problem. Below are some of them:
Defective temperature switch or coolant sensor
If your car's fan blade stops working, then there must be something wrong with the temperature switch or the coolant sensor. You will also find that this is the problem when your vehicle is using up more gas than usual. You can confirm this by running your car through an emissions test. If all of its parts are in order except for the cooling system, then this means that either the temperature switch or the coolant sensor is faulty.
Engine thermostat is stuck open
Over time, the engine thermostat will just quit working and get stuck open. When this happens, your Jeep's fan blade will not work as well. To test the thermostat and find out if this has caused the blade to fail, you will need access to the radiator cap. First, make sure that both the radiator and engine have cooled down, the parking brake is engaged, and the wheels have been blocked. Then, remove the radiator cap, fire up the engine, and let it idle. Look through the cap and check the coolant's movement. Note that it should not be flowing at all since the coolant has not reached enough temperature to make the thermostat open. However, if you do see it flowing, then this means the thermostat is stuck open and you will need to replace it.
Other quick checks
To quickly check the fan circuit, start the engine and turn on the air conditioner to max. If the fan blade runs, then the fan motor, relay, fuse, and wiring are all okay. However, note that this doesn't show whether the temperature switch or sensor and powertrain control module are energizing the fan. You will need to check these components separately.