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This is normal in many vehicles, such as BMW or Mercedes-Benz. The radiator fan may run up to five minutes and sometimes longer. Unless there is an electrical issue, it may stay on all the time until it drains the battery. Running cooling fans help cool down the engine even after you turn off the car.
What causes a radiator fan to run constantly?
The situation when the car radiator cooling fan keeps running constantly can be caused mostly by a failing coolant temperature sensor or its wiring, broken fan start relay, damage to the electrical wires, electronic engine control unit (ECU) problems. Failing coolant temperature sensor or damage to its wiring.
How do I stop my radiator fan from running?
My Cooling Fan Won’t Stop Running on My Radiator Open the hood and locate the fuse relay box on the driver’s fenderwell. Remove the lid. Look on the inside of the lid and for the mapping of the fuses and relays with their location. Pull the cooling fan relay out of the box. Replace the cooling fan relay with a new one.
Are radiator fans supposed to run all the time?
Temperature will often determine the time that a radiator fan starts up. A temperature-sensitive switch functions to turn the fan on and off periodically. Radiator fans are designed to start when the temperature of the engine coolant reaches around 200 degrees Fahrenheit.
How do I know if my radiator fan relay is bad?
Bad Cooling Fan Relay Symptoms The engine runs hot or overheats. The cooling fans don’t work. The cooling fans keep running. Warning lights. Poor air conditioning performance. Swapping Relays. Measuring the Relay Coil’s Resistance. Listening for Noises.
Why is my car fan still running when car is off?
So its quite normal for fans to keep running after the engine is cut off… it helps cool the radiator down gradually. It’s normal. The electric fan is running independently of the engine in order to bring down the temperature of the coolant in the radiator.
How often should radiator fan come on?
But, on a normal 70–80 degree day you should hear the fan run, I would guess, after about 15 to 20 minutes of idling from a cold start. When the electric cooling fan operates is purely a function of the setting of the temperature switch used to control power to the fan.
Is there a fuse for the radiator fan?
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. The fan itself often uses a big fuse of around 50A, while there might also be a separate small fuse to the fan control module.
Should both radiator fans be on?
Both fans should come on when the A/C is on. If one or both fans fail to come on, the lack of additional cooling provided by the fan may cause poor A/C cooling performance, and it may cause the A/C compressor to overheat and fail.
Where is the relay switch for a radiator fan?
The fan relay is usually located near the bottom of the engine compartment on a metal frame member. The metal acts as a heat sink to keep the fan relay cool. So, unplug the connector at the relay and repeat the check for power.
Can low coolant cause fan to stay on?
Usually, a low coolant will equate to a hotter engine. Therefore, it will activate the fan more often.
What sensor controls the radiator fan?
On most modern cars, the cooling fan is controlled by the Engine Control Unit (ECU) which gets a signal from the coolant temperature sensor.
Does the coolant temperature sensor control the fan?
The sensor works by measuring the temperature that’s being given off by the thermostat and/or the coolant itself. The temperature is then sent to the on-board control system. As the control system receives the temperature from the CTS, it may trigger the cooling fan to either shut off or turn on.
How can you tell if a fan fuse is blown?
Look at the fuse wire. If there is a visible gap in the wire or a dark or metallic smear inside the glass then the fuse is blown and needs to be replaced.
How do you diagnose cooling fan problems?
To check the temperature at which the fan comes on, turn the A/C off and keep the engine running until it reaches normal operating temperature. Most fans should come on when the coolant reaches about 200 to 230 degrees. If the fan does not come on, something in the control circuit is defective.
Is radiator fan connected to AC?
The condenser fan (if it has a dedicated fan) or the radiator fan most always comes in (with AC on) when the compressor discharge pressure (or, alternatively, the liquid line one; look for where a sensor or a switch is located on the high pressure line) rises over an operative threshold.
How much does it cost to replace a radiator fan?
The average radiator fan replacement cost is typically between $550 and $650. In many cases, the radiator fan will cost around $400 to $450, while the labor adds $150 to $200. However, some vehicles can be more expensive, depending on the design.
How much is a fan relay?
The average for Cooling Fan Relay is $478 Repair Type Zip Cost Cooling Fan Relay 13045 $373 Cooling Fan Relay 78452 $464 Cooling Fan Relay 23359 $596.
How do you know if your radiator is clogged up?
Remove the radiator cap on a cold vehicle. Turn your mobile flashlight on and check out the inside of the radiator. If the radiator fluid seems like mud water or it smells like rubber, or if the radiator fins are corroded with white crusty deposits, then it is a clogged radiator.
Where is the cooling fan sensor located?
It is most often located close to the thermostat of the cooling system or inside of it. The cooling system is located beneath the air intake pipe and behind the right cylinder.
