Why Is My Fan Running When Truck Is Off?

We all have one moment in our life, while we are leaving our car after traveling, we hear the engine radiator fan spinning at a good pace, and always the question arises why is the fan running when the truck is off? We have the answers.

When the engine is turned on, the coolant circulates and goes to the radiator, where it dissipates heat. When the engine is shut off, the coolant does not circulate and the heat is trapped, causing the engine to overheat. Running cooling fans keep the engine cool even after you turn off the engine.

Should You Worry About Your Running Fan?

No, This is very acceptable and natural. The explanation for this is straightforward. The ECU unit instructs the fan to continue working after the engine is turned off since the coolant is still heated. It continues to run, making some noise until the temperature returns to normal. Don’t worry it’s alright.

But, if your fun runs for 15 minutes or more there must be a problem in your fusebox which can be Most contemporary electric fans contain modules that instruct them when to turn on and off. It’s conceivable that a module or relay in your vehicle is failing. Inspect the electrical part of your cooling system to ensure it is operating properly.

How To Inspect Problems Causing Fan Running When Truck Is Off?

Problems in electrical systems can happen anytime, depends on your habit of maintaining your truck to inspect your problem these are the procedures:

1. Checking Engine Heat Levels-

Car Temp

Check the temperature gauge in the automobile for an analysis. If the needle is still in the center, or if it’s a digital dash, and the temperature is normal, your car may or may not have overheated.

The cooling fans keep the radiator cold while the combustion engine heats up due to the burning gasoline flowing through it. The friction created by moving pistons generates a lot of heat as well. Overheating will be indicated by your temperature needle.

2. Checking Coolant Levels-


Sometimes problems like this occur due to the low amount of coolant in the system which leads to overheating, Overheating is frequently corrected by adding coolant (if it is low) or replacing the oil. An automobile without oil is dangerous. This can produce a cracked or a blown engine. Which can cause the fan running when truck is off

3. Checking Sensors-


The temperature sensors in the car may have gone bad which can be causing the fans to spin continuously and draining the battery of your car just unplug the terminals from the battery and wait for it to stop and replace the part of the sensor that may have gone bad.

How to Fix Running Fan In Truck?

It’s a simple procedure to fix out your relay or sensory which may have gone wrong and is causing the fan to spin the procedure is-

Step: 1. Inspection


Before coming to any conclusion first thing is to do a thorough inspection. Run your car for a few kilometers and heat up your engine come and park it and let the fan run, Check the running time if it runs for 15-25 minutes it’s fine otherwise we might have some issue which includes

  1. Low Coolant Level
  2. Low On Engine Oil
  3. Fuse or Relay Gone Bad
  4. Temperature Sensor Went Bad
  5. ECM Can’t Read Temperature

Step: 2. Checking Parts

  1. Coolant Level-  Sometimes using the car aggressively causes the coolant level to go down or coolant becomes unusable or the pipes get clogged, If all of these happen it may lead the vehicle to overheat which leads to the fans running continuously even after turning off.Engine oil
  2. Engine Oil- Less amount of engine oil also cause overheating problems due to an increase in wear and tear and less lubrication so check it by pulling the dipstick out if the amount is less drain the old one and fill it with new.Fuse
  3. Fuse or Relay- Fuse and Relay are the crucial parts that must be checked sometimes it goes direct which leads the fan to run even after cutting the ignition grab your multimeter and check for the relay voltage.Meter
  4. Temperature Sensor- It is the main part of the vehicle which brokes down very quickly and gives different readings to the computer which chooses different measures to control the temperature.Sensor
  5. ECM Error- ECM is the brain of the car and if the brain gets wrong info or no info it’ll work in different ways to fix the issues,  This same happens in the car when the sensors go bad computer can’t get enough data and send wrong analysis to parts which also leads to the fans to run

Truck Sensor Replacement

Fixing Sensors and  Relays is a bit of a job to do. But with our post, you can do it very easily at home with less tools.

Step 1: Cooling The Car

Engine coolin

If you have driven the car for some time let it cool down to start the work as a hot engine may cause severe injury to the body, So let it cool down.

Step 2: Locating The Sensor


Find the coolant temperature sensor. It is often located near the thermostat housing, however, it can be located in any engine cooling path. A repair manual will tell you where to search, but if you don’t have one, look for a radiator hose with an electrical hookup nearby.

Step 3: Replacing The Sensor

Unscrew the coolant temperature sensor from the coolant route with a tool. In small places, a ratcheting wrench may save a lot of time.
Replace the sensor. Torque the electrical plug to ensure it firmly snaps on.

Step 4: Flushing and Adding New Coolant


After doing all the replacements, flush out your old coolant and fill it with the new one. So there will be less chance of overheating and also less chance of fan running when truck is off


It’s not a huge problem to be worried about Yes, you can drive your truck as you were but precaution is better than cure. So get your truck checked for what causing the fan running when truck is off. we have given you methods to try on and yes you can contact your dealership for this fix if you are not confident.

Happy Driving!

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