Ford F-150 Radiator Fan Running Constantly: Causes & Fixes
The Ford F150 is a popular pickup truck known for its reliability and performance. However, some F150 owners report the electric cooling fan running constantly, even when the engine is not hot. A fan that runs for a few minutes after shutdown is normal. Ford’s owner’s manuals warn that, under certain conditions, the engine cooling fan can keep running for several minutes after you switch the vehicle off. A fan that never shuts off, or that runs long enough to drain the battery, is not normal.
A fan that won’t shut off can drain the battery and wear out the fan motor. In this guide, we will explore the common causes of this issue and provide step-by-step instructions for solving it.
Common causes of the radiator fan constantly running
There are several reasons why the radiator fan may run constantly in the Ford F150. Some of the most common causes include: One common cause of the radiator fan running constantly in the Ford F150 is a faulty coolant temperature sensor. When this sensor malfunctions, it can send the wrong signal to the fan, causing it to run constantly. A thermostat stuck closed can make the engine run hot, which also keeps the fan on. On 2015–2022 F-150s, Ford TSB 22-2089 also covers engine cooling fans running continuously alongside poor A/C performance. It traces this to a biased evaporator temperature sensor; see the note below. If the fan drains the battery, you may also see a no-start. It’s important to address any issues with the radiator fan promptly to prevent further damage to the vehicle.
- Faulty Relay
The relay is an electrical switch that controls the power to the radiator fan. If the relay is faulty, it may cause the fan to run continuously.
- Damaged Wiring
The wiring connected to the radiator fan can become damaged due to exposure to heat, moisture, and other elements. This can cause the fan to run continuously.
- Coolant Temperature Sensor
The coolant temperature sensor is responsible for monitoring the temperature of the coolant and sending a signal to the fan relay. If the sensor is faulty, it may send a signal to the fan relay to run the fan continuously, even if the engine is not overheating.
- Problems with the PCM or Programming
The PCM (Powertrain Control Module) is responsible for controlling many of the electrical systems in the vehicle, including the radiator fan. If there is a problem with the PCM or its programming, it may cause the fan to run continuously.
- Overloading or Towing Heavy Loads
Overloading your vehicle or towing heavy loads can put additional stress on the engine, causing it to run hotter than normal. This can cause the fan to run continuously to keep the engine cool.
- Low Coolant Level
If the coolant level in your vehicle is low, it can cause the engine to overheat, triggering the fan to run continuously.
- Engine Overheating
Engine overheating is one of the most common causes of the radiator fan running continuously. If the engine is overheating, the fan will run continuously to try to cool it down.
- Clogged Radiator
If the radiator is clogged with debris or sludge, it can restrict the flow of coolant, causing the engine to overheat and triggering the fan to run continuously.
- Failed Fan Motor
If the fan motor has failed, it can cause the fan to run continuously or not turn on at all.
- Faulty Coolant Fan Switch
On modern F-150s, the PCM switches the electric fan through relays or a fan control module, based on sensor inputs; there is generally no separate thermostatic fan switch like on older vehicles. Check your year’s wiring diagram before buying a “fan switch.”
How to diagnose the issue with the radiator fan
To diagnose the issue with the radiator fan, you need to perform a series of checks.
- Check the Relay
If the relay is faulty, it can cause the fan to run continuously. To check it, pull the fan relay with the engine off and swap in a known-good relay of the same part number; if the fan now shuts off normally, replace the old relay.
- Inspect the Wiring
If the wiring connected to the radiator fan is damaged, it can cause the fan to run continuously. To diagnose this issue, you can visually inspect the wiring for any frayed or damaged wires, and check for any loose connections.
- Check the Coolant Temperature Sensor
If the coolant temperature sensor is faulty, it can cause the fan to run continuously. To diagnose this issue, compare the sensor’s reading on a scan tool with actual engine temperature. You can also measure its resistance against the service manual chart for your engine.
- Inspect the PCM
If there is a problem with the PCM or its programming, it can cause the fan to run continuously. To diagnose this issue, you can have a professional diagnose the PCM using a diagnostic scan tool.
- Check the Engine Overheating
Engine overheating can cause the fan to run continuously. To diagnose this issue, you can check the temperature gauge on your dashboard or use a thermometer to check the temperature of the engine.
- Inspect the Radiator
If the radiator is clogged with debris or sludge, it can cause the engine to overheat and trigger the fan to run continuously. To diagnose this issue, you can inspect the radiator for any signs of debris or clogging.
- Check the Fan Motor:
If the fan motor has failed, it can cause the fan to run continuously or not turn on at all. To diagnose this issue, you can use a multimeter to check the resistance of the fan motor and see if it’s functioning properly.
- Inspect the Coolant Fan Switch
If your truck’s wiring diagram shows a fan switch or fan control module, test it as the service manual describes. On most modern F-150s, the PCM controls the fan, so a scan tool showing fan command and coolant temperature is the faster check.
- Check for Low Coolant Level
If the coolant level in your vehicle is low, it can cause the engine to overheat and trigger the fan to run continuously. To diagnose this issue, you can check the coolant level in the engine and make sure it’s at the correct level.
- Consult a Professional Mechanic
If you are unable to diagnose the issue with the radiator fan, it’s always best to consult a professional mechanic. They have the experience and knowledge to properly diagnose and repair the issue.
10 Steps to replace the radiator fan
If you determine that the radiator fan is the root of the problem, you will need to replace it. Here are the steps to replace the radiator fan in your Ford F150:
- Prepare the Vehicle
Before replacing the radiator fan, park your vehicle on a flat surface and let it cool down. Make sure to gather all necessary tools and supplies, including a new radiator fan, wrenches, pliers, and gloves.
- Locate the Radiator Fan
The electric fan sits behind the radiator, usually in a shroud bolted to the radiator support. You may need to remove the engine cover, air intake parts or the shroud to reach it; follow your year’s service manual.
- Disconnect the Electrical Connections
Before removing the radiator fan, disconnect the negative battery cable, then unplug the fan motor connector.
- Remove the Mounting Bolts
Once the electrical connections have been removed, use a wrench or socket to remove the fasteners that hold the fan and shroud assembly in place.
- Install the New Radiator Fan
Place the new radiator fan in position and tighten the bolts to secure it in place. Reconnect the fan connector and the battery cable.
- Test the Fan
After the new radiator fan has been installed, start the engine and run the fan to make sure it’s functioning properly. Check for any signs of vibration or noise, and ensure that the fan is running smoothly.
- Replace the Engine Cover and Fan Shroud
If necessary, replace the engine cover and fan shroud that was removed in step 2.
- Refill the Coolant
If any coolant was lost during the replacement process, refill the coolant to the correct level.
- Check for Leaks
Check the area around the radiator fan for any signs of leaks or coolant drips. If you find any leaks, it’s important to address them promptly to prevent further damage.
- Final Check
Finally, inspect the entire system for any issues or problems. Make sure everything is functioning properly and that there are no signs of leaks, vibrations, or noise. If everything checks out, you’re ready to hit the road!
Checking the relay and wiring
To check the relay and wiring, follow these steps:
- Locate the Relay
The relay that controls the radiator fan is usually located in the engine bay near the battery. Consult your vehicle’s manual for its exact location.
- Identify the Relay
The relay will be a small box with several connectors and wires. It will usually be labeled as the radiator fan relay or the cooling fan relay.
- Check the Connections
Before testing the relay, make sure all connections are clean and tight. Check for any signs of corrosion, fraying, or damage.
- Test the Relay
A relay that sticks closed keeps the fan running even with the key off. With the engine off and the fan running, pull the fan relay(s) listed in your owner’s manual fuse chart; if the fan stops, swap in a known-good relay of the same part number and recheck.
- Check the Wiring
If the relay is functioning properly, inspect the wiring that connects the relay to the fan motor. Check for any signs of damage, fraying, or corrosion. If you find any issues, you may need to repair or replace the wiring.
- Test the Fan Motor:
If the wiring is in good condition, test the fan motor by connecting a multimeter to the fan motor connections. If the fan motor doesn’t work, it may need to be replaced.
- Check the Coolant Temperature Sensor
Finally, inspect the coolant temperature sensor that controls the radiator fan. This sensor is usually located near the radiator and may have a single wire or several wires connected to it. Test it by measuring resistance (or checking the scan tool reading) against the service manual values for your engine. A simple continuity check doesn’t prove the sensor is reading correctly.
- Fix Any Issues
If you find any issues with the relay, wiring, fan motor, or coolant temperature sensor, repair or replace them as necessary.
- Final Check
After making any repairs, test the radiator fan again to make sure it’s functioning properly. If everything checks out, you can be confident that your vehicle’s cooling system is in good working order.
Checking the coolant temperature sensor
To check the coolant temperature sensor, follow these steps
- Understanding the Coolant Temperature Sensor
The coolant temperature sensor is an important component of the radiator fan system. It helps to regulate the temperature of the engine and to activate the radiator fan when needed.
- Locating the Sensor
The coolant temperature sensor is usually located near the radiator, and it may have a single wire or several wires connected to it. Consult your vehicle’s manual for its exact location.
- Testing the Sensor
To test the coolant temperature sensor, you’ll need a multimeter. Measure the sensor’s resistance at a known temperature and compare it with the service manual chart, or compare its scan tool reading with the actual engine temperature. A reading far off the chart means the sensor may need to be replaced.
- Checking the Wiring
In addition to testing the sensor, inspect the wiring that connects the sensor to the fan relay. Check for any signs of damage, fraying, or corrosion. If you find any issues, you may need to repair or replace the wiring.
- Testing the Radiator Fan
After making any necessary repairs, test the radiator fan again to make sure it’s functioning properly. If everything checks out, you can be confident that your vehicle’s cooling system is in good working order.
- Importance of Regular Maintenance
Regular maintenance, including checking and testing the coolant temperature sensor, is important to ensure the efficient operation of your vehicle’s cooling system. Neglecting this important component can lead to overheating, engine damage, and other serious issues.
Checking the coolant temperature sensor is an important step in maintaining your vehicle’s cooling system. By testing the sensor and fixing any issues, you can help prevent overheating, engine damage, and other serious problems.
Checking the PCM and programming
To check the PCM and programming, follow these steps:
- Understanding the Powertrain Control Module
The powertrain control module (PCM) is an important component of your vehicle’s engine control system. It helps to regulate the operation of various components, including the radiator fan.
- Identifying PCM Issues
If the PCM is not functioning properly, it can cause the radiator fan to run constantly. Some common symptoms of a malfunctioning PCM include warning lights on the dashboard, strange noises, and sudden engine shut-off.
- Scanning for Codes
To diagnose a PCM issue, you’ll need to scan the vehicle’s onboard computer for diagnostic trouble codes (DTCs). This can be done with a specialized diagnostic tool or at a repair shop.
- Reprogramming the PCM
If the scan reveals a programming issue with the PCM, it may need to be reprogrammed. This can be done by a professional mechanic or at a repair shop.
- Checking the Wiring
In addition to reprogramming the PCM, it’s important to inspect the wiring that connects the PCM to the radiator fan. Check for any signs of damage, fraying, or corrosion. If you find any issues, you may need to repair or replace the wiring.
- Testing the Radiator Fan: After making any necessary repairs, test the radiator fan again to make sure it’s functioning properly. If everything checks out, you can be confident that your vehicle’s cooling system is in good working order.
Conclusion: In conclusion, checking the PCM and programming is an important step in maintaining your vehicle’s cooling system. By scanning for codes, reprogramming the PCM, and fixing any issues with the wiring, you can help prevent the radiator fan from constantly running.
Tips to prevent the radiator fan from constantly running
To prevent the radiator fan from constantly running, here are some tips to keep in mind:
- Regular Maintenance
Regular maintenance, including checking and testing the coolant temperature sensor, is the best way to prevent the radiator fan from constantly running.
- Keep the Engine Cool
Keeping the engine cool is essential to prevent overheating and to ensure the efficient operation of your vehicle’s cooling system. Avoid prolonged idling, and make sure to allow the engine to cool down after driving.
- Use High-Quality Coolant
Using high-quality coolant can help to prevent overheating and to ensure the efficient operation of your vehicle’s cooling system. Make sure to use the recommended coolant for your vehicle, and have it changed at regular intervals.
- Check the Radiator and Hoses
Regularly check the radiator and hoses for any signs of damage, leaks, or corrosion. If you find any issues, have them repaired as soon as possible to prevent overheating.
- Drive Carefully
Heavy towing and hot weather make the fan run more. That’s normal, as long as it shuts off once the engine cools.
- Check the Radiator Fan
Regularly check the radiator fan to make sure it’s functioning properly. If you find any issues, have them repaired as soon as possible to prevent the radiator fan from constantly running.
- Stay Alert
Keep an eye out for warning signs of a malfunctioning cooling system, including high engine temperatures, low coolant levels, and warning lights on the dashboard. If you notice any of these signs, have your vehicle inspected as soon as possible.
By following these tips and by performing regular maintenance, you can help prevent the radiator fan from constantly running. By taking care of your vehicle’s cooling system, you can help ensure the efficient operation of your vehicle and prevent serious problems.
Cost considerations for fixing the radiator fan issue
The cost of fixing the radiator fan issue in your Ford F150 will depend on the cause of the problem and the parts and labor required to fix it. Costs vary widely with the part and labor needed. A relay is usually the cheapest fix, while a fan assembly, sensor or module costs more, and wiring faults depend on how long diagnosis takes. It is important to get an accurate estimate from a professional mechanic to determine the cost of fixing this issue.
Ford F150 fan running – FIXED!!!
2016 Ford F150 Fan Keeps Running After Car Turned off
If you’re driving a 2016 Ford F-150, you may have noticed that the fan keeps running after you turn the car off. This is a design flaw that has been noted by many owners and it can be quite annoying, especially if you’re trying to enjoy some peace and quiet. The good news is that there are a few things you can do to fix this problem.
First, check to see if your car has the latest software update. A Ford dealer can check whether any PCM software updates or TSBs apply to your VIN. We couldn’t confirm a specific 2017 update for this issue, so ask the dealer to check your VIN.
Disconnecting the battery will stop the fan for now, but it won’t fix a stuck relay or bad sensor. Keep clear of the fan, since it can start without warning. Check the relay and sensor first, before replacing the fan assembly.
A relay swap is an easy DIY job; a fan assembly takes more work.
If you’re dealing with this annoying problem, don’t despair! There are a few things you can do to fix it.
If the fan runs continuously and the A/C is also blowing warm, ask the dealer about TSB 22-2089 (2015–2022 F-150).
2012 Ford F150 Cooling Fan Runs Constantly
Depending on the engine, a 2012 F-150 may use a belt-driven fan with a clutch rather than an electric fan, so check which one your truck has. A fan that runs for a few minutes after shutdown can be normal; one that never stops is not.
If it keeps running well after shutdown or drains the battery, diagnose it using the steps above.
2018 Ford F150 Fan Keeps Running
If your 2018 Ford F-150 fan keeps running after you turn the engine off, there are a few potential causes. It could be something as simple as a loose wire or fuse, or it could be a more serious issue like a faulty sensor. Here are a few things to check if your F-150’s fan won’t shut off:
1. Check the fan fuse: The fan fuses and relays are in the engine compartment fuse box; your owner’s manual lists them. For example, the 2023 F-150 manual lists two 50 A cooling fan fuses (47 and 49). A blown fan fuse stops the fan from running; it does not keep it on. A fan that won’t shut off points to a stuck relay, a sensor, or the fan control circuit. 2. Check for loose wires: There are several wires that run to the fan motor, and if any of them are loose, it can cause the fan to keep running.
Inspect all of the wires carefully and make sure they’re all securely connected. 3. Check for a faulty sensor: There are various sensors around the engine that tell the computer when to turn on and off the fan. If one of these sensors is defective, it can cause the fan to stay on even after you shut off the engine.
2014 Ford F150 Fan Runs All the Time
If you’re like most people, you rely on your Ford F-150 to get you where you need to go. But what happens when your fan starts running all the time?
There are a few possible causes for this problem.
The most common one is a fan relay sticking closed. A faulty coolant temperature sensor or fan control circuit can also keep the fan on.
If your fan is running all the time, it’s important to have it checked out by a qualified mechanic as soon as possible.
Running the fan continuously can put a strain on the electrical system and may cause other problems down the road.
4 Most Frequently Asked Questions
What causes the radiator fan to run constantly in the Ford F150?
The most common causes of the radiator fan running constantly in the Ford F150 include a faulty relay, damaged wiring, a faulty coolant temperature sensor, and problems with the PCM or programming.
How do I diagnose the issue with the radiator fan in my Ford F150?
To diagnose the issue with the radiator fan, you need to perform a series of checks including checking the relay and wiring, the coolant temperature sensor, and the PCM and programming.
Can I replace the radiator fan myself in my Ford F150?
Yes, you can replace the radiator fan yourself in your Ford F150. Confirm the fan is actually the cause first (often it’s the relay), then follow your year’s service manual procedure.
How much does it cost to fix the radiator fan issue in my Ford F150?
The cost of fixing the radiator fan issue in your Ford F150 will depend on the cause of the problem and the parts and labor required to fix it. A stuck relay is usually the cheapest fix; fan assemblies, sensors and wiring repairs cost more. Get a written estimate.
Conclusion and resources for further information
In conclusion, the radiator fan constantly running issue in the Ford F150 is often caused by a stuck relay or sensor fault, and can lead to a dead battery if ignored.
By following the steps outlined in this blog post, you can diagnose and fix the issue to keep your vehicle running smoothly. For more information on this issue, be sure to consult your Ford F150 owner’s manual and professional mechanic.
