Why does the radiator fan come on when the car is not running?

Why does the radiator fan come on when the car is not running?

On some modern vehicles, an ambient air temperature sensor, vehicle speed sensor, and other sensors may provide input to the car computer to determine radiator fan operation. Consult your vehicle repair manual to check the required sensors and switches. On a warm engine, the fan may come on even if the engine is not running.

Where is the temperature sensor on a radiator fan?

The sensor is usually located in the car thermostat cover. To check it, disconnect the wires from the sensor and touch them together. If this starts the fan, the sensor is faulty and will need to be replaced. Check your service manual to make sure exactly where the temperature sensor is on your car.

What happens when you turn off the radiator in a car?

Deprived of the helpful influx of air from the cooling fans, the radiator cannot remove as much heat as it usually does. It sends still-hot coolant back to the engine, causing temperatures to rise as the coolant fails to do its job of cooling down the motor.

What happens when a radiator relay goes bad?

A faulty or broken relay cannot deliver power to the cooling fans. In turn, the unpowered fans won’t run, leaving the radiator to its own devices. Deprived of the helpful influx of air from the cooling fans, the radiator cannot remove as much heat as it usually does.

Why is the radiator fan on my car not working?

When the thermostat in front of the engine detects that the engine reaches a dangerous temperature, the radiator then kicks in by releasing a mixture of water and coolant to quickly cool down the engine. There is a sensor on the bottom passenger side of the radiator. It does the job of taking notes of coolant temperature.

The sensor is usually located in the car thermostat cover. To check it, disconnect the wires from the sensor and touch them together. If this starts the fan, the sensor is faulty and will need to be replaced. Check your service manual to make sure exactly where the temperature sensor is on your car.

Deprived of the helpful influx of air from the cooling fans, the radiator cannot remove as much heat as it usually does. It sends still-hot coolant back to the engine, causing temperatures to rise as the coolant fails to do its job of cooling down the motor.

How to repair a cooling fan in your car?

Cooling fan. How to repair a cooling fan in your car DIY with Scotty Kilmer. How to inspect and repair a cooling fan that’s not working. There’s many reasons why a cooling fan could stop working, such as a bad sensor, relay, fuse and more. DIY car repair with Scotty Kilmer, an auto mechanic for the last 42 years. 1.

What should I do if my car fan won’t turn on?

On modern vehicles, a bad sensor usually triggers the check engine light. Scan the computer for trouble codes, if necessary. If the fan fails to come on, first check for a fan blown fuse or triggered breaker. On older vehicle models, you may have a fusible link in the circuit.

How to troubleshoot an electric cooling fan problem?

1.Has the Cooling Fan Actually Failed? 1 If the fan comes on when the AC is running at MAX, but doesn’t run when the engine is hot, check the temperature sensor… 2 If the fan fails to come on, first check for a fan blown fuse or triggered breaker. On older vehicle models, you may… More …

Why is my AC not working in my car?

If this is the case the hot refrigerant will only be cooled back down to ambient temperature so your AC won’t work. Since the condenser is at the front of your vehicle, it has the opportunity to get clogged by all kinds of road debris from leaves to plastic bags or anything else you might drive into.

What does it mean when your radiator fan is not working?

This is what we call a blown fuse. A blown fuse is no big deal, and changing one does not cost a lot of money. If your car’s radiator fan is non-functional, check your car’s user manual and locate the fuse for the radiator fan controller or the fan.

What to do if your Dodge Grand Caravan radiator does not turn on?

Test the resistance of the wire harness between the PCM connector terminal 26 and the sensor harness connector. Also check for continuity between PCM connector terminal 43 and the sensor harness connector. If the resistance is greater than 1 ohm , repair the wire harness as necessary.

Where is the radiator fan relay on a Dodge Grand?

If the Radiator fan control module has failed you will need to replace it with a new one there is no way to repair it. The radiator fan relay is located below the left front headlamp module. The headlamp module must be removed to access the relay. Open hood, disconnect and isolate the battery negative cable.

Is there a way to test a radiator fan?

You can test the electrical radiator fans by taking a wire from the car battery, unplug the radiator fan connector, and put 12v+ and ground into the connector. This is the fastest and easiest way to test your radiator fans. Because the radiator fan is often drawing so much power, there is often a relay that is powering the coolant fan.

Can a radiator fan and condenser fan share a relay?

There are, however, some models that use a dedicated second unit to the condenser. In such a scenario, the condenser fan and radiator fan may or may not share the same relay. If the cooling fan does not engage, you can check whether the relay is to blame by swapping it out for a different relay.

On some modern vehicles, an ambient air temperature sensor, vehicle speed sensor, and other sensors may provide input to the car computer to determine radiator fan operation. Consult your vehicle repair manual to check the required sensors and switches. On a warm engine, the fan may come on even if the engine is not running.

A faulty or broken relay cannot deliver power to the cooling fans. In turn, the unpowered fans won’t run, leaving the radiator to its own devices. Deprived of the helpful influx of air from the cooling fans, the radiator cannot remove as much heat as it usually does.

How to test if a Honda radiator fan is working?

Here is how to test if the fan is functioning properly: 1 Unplug the radiator fan connector. 2 Run jumper wires between the connector’s two electrical terminals. See Contact Test in Step 1. 3 If the fan does not turn on, you will need to replace it.