2020 Mercedes-Benz C43 AMG Radiator Fan Isn't Working

Fixing the Non-Functioning Radiator Fan in 2020 Mercedes-Benz C43 AMG

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Reviewed by
Aisha
Written by RepairPal Car Genius
Updated January 14, 2025
0%
34% chance it's the
Fan Motor or Clutch
0%
28% chance it's the
Fan Relay or Fuse
0%
23% chance it's the
Temp Sensor or Fan Control Module
0%
15% chance it's
Something else
The most common reasons a 2020 Mercedes-Benz C43 AMG radiator fan isn't working are the fan assembly, the fan clutch, or the coolant temperature sensor.
  • Fan Motor or Clutch: A faulty fan motor or a malfunctioning fan clutch can result in inadequate cooling, causing the engine to overheat.
  • Fan Relay or Fuse: A faulty fan relay or blown fuse can prevent the cooling fan from operating, leading to engine overheating.
  • Temp Sensor or Fan Control Module: A faulty temperature sensor or fan control module can result in incorrect readings, causing the engine to overheat or the cooling fan to operate improperly.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2020 Mercedes-Benz C43 AMG radiator fan isn't working?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

Over time serpentine belts stretch, crack, and the ribs that ride on the accessory pulleys being to wear smooth. A squealing noise that increases with engine speed or as engine driven accessories are turned on may be noted. The noise is caused by the belt slipping on the pulleys, insufficiently driving them. Ineffective air conditioning, a battery warning light, or intermittent power steering assist can result from this.

»MORE: Symptoms of a bad serpentine belt

The bad thermostat can cause two different sets of problems, depending on whether it's stuck open or stuck closed.

A thermostat that is stuck open can cause the engine to run colder than normal and turn on the check engine light. It may also cause poor fuel mileage and the heater to blow cool air.

A thermostat that is stuck closed will cause the vehicle to overheat. If a new thermostat doesn't resolve engine temperature problems, the cooling system needs to be checked for other issues.

» LEARN MORE: Signs of a bad thermostat, and how to fix it

When the engine coolant temperature sensor fails, it will send inaccurate information to the vehicle’s computer, causing the computer to react to false operating conditions. This will cause the engine to consume more fuel than normal, depleting fuel mileage, and causing black, sooty smoke from the engine under moderate to heavy acceleration. The check engine light will illuminate, and on-board diagnostic trouble codes may be stored for exhaust and emission system failure, fuel delivery system failure, and engine cooling system failure. Overheating may also occur, as the coolant sensor may be leaking fluid out of the engine, creating a an air pocket in the system.

When the radiator fans stop functioning properly, the engine temperature will rise. The spike in temperature will be highest when the vehicle is idling at a stop, but should subside once the vehicle begins moving again.

Additionally, the air conditioner typically won't blow as cold. This is because the air from the radiator fans also blows across the air conditioning condenser, so when the fans fail, both systems suffer.

You'll also usually see the check engine light and notice a drop in fuel economy. It's possible the fan will start making noise if it's failing, as well.

What are the initial diagnostic steps to take when the radiator fan isn't working on a 2020 Mercedes-Benz C43 AMG?

When faced with a non-functioning radiator fan in your 2020 Mercedes-Benz C43 AMG, it's essential to adopt a systematic diagnostic approach. Begin by checking the fuse associated with the radiator fan, as a blown fuse is a common and easily rectifiable issue. If the fuse is intact, proceed to inspect the relay that controls the fan; a malfunctioning relay can disrupt the power supply to the fan. Next, test the fan motor itself to confirm it operates correctly, as a defective motor will prevent the fan from spinning. Additionally, examine the temperature sensor, which is vital for activating the fan when the engine reaches a certain temperature; ensuring its proper function is crucial. Don't overlook the wiring and connections; loose or damaged wires can lead to intermittent or complete fan failure. Finally, if the problem persists, using a diagnostic scanner to check for error codes can provide deeper insights into any underlying issues within the cooling system. By following these steps, you can effectively diagnose and potentially resolve the radiator fan issue on your own.

What are the common problems that could cause the radiator fan to stop working in a 2020 Mercedes-Benz C43 AMG?

When diagnosing why the radiator fan in your 2020 Mercedes-Benz C43 AMG has stopped working, it's crucial to consider several common problems that could be at play. A faulty fan motor is often the primary suspect, as it can fail to spin, leading to engine overheating. Additionally, a blown fuse in the fan circuit can interrupt the power supply, effectively shutting down the fan. Another potential issue is a defective temperature sensor, which may fail to signal the fan to activate when the engine reaches high temperatures, resulting in inadequate cooling. Furthermore, a worn or broken fan belt can hinder the fan's operation, while a coolant leak can lower coolant levels, preventing the fan from receiving the necessary fluid to cool the engine effectively. Addressing these issues promptly is essential to maintain your vehicle's cooling system and prevent engine damage, making it vital for DIY enthusiasts to be aware of these common problems.

How urgent is it to address the non-functioning radiator fan in a 2020 Mercedes-Benz C43 AMG?

Addressing a non-functioning radiator fan in your 2020 Mercedes-Benz C43 AMG is not just a matter of convenience; it is an urgent necessity. The radiator fan is essential for regulating the engine's temperature, and when it fails, the risk of overheating escalates dramatically. Overheating can lead to severe engine damage, resulting in costly repairs or even the need for a complete engine replacement. Moreover, driving with a malfunctioning fan compromises your vehicle's performance and efficiency, which can affect your overall driving experience. Ignoring this issue can also pose serious safety hazards, as an overheated engine can lead to unexpected breakdowns or, in extreme cases, a fire risk. Therefore, it is crucial to address any signs of a failing radiator fan immediately to safeguard your vehicle's performance and ensure your safety on the road.

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