2004 Mercedes-Benz G500 Radiator Fan Isn't Working

Radiator fan not working in 2004 Mercedes-Benz G500: causes and solutions

Find Repair Location
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 2004 Mercedes-Benz G500 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 2004 Mercedes-Benz G500 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 first indication of a defective fan clutch is a healthy cooling system that runs below or above the normal temperature range. This is due to the fan running too fast or too slow. Also, a seized cooling fan will cause a loud roaring fan noise from under the hood every time the accelerator is pressed, and the engine will feel as if it lacks power. In this situation it would be very difficult to turn the engine cooling fan by hand, of course when the vehicle is off. Finally, if the clutch fails the fan will either turn very slowly, and not respond well to engine speed.

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.

What are the initial diagnostic steps to take when the radiator fan isn't working on a 2004 Mercedes-Benz G500?

When faced with a non-functioning radiator fan in a 2004 Mercedes-Benz G500, 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, the next step is to inspect the relay that controls the fan; a faulty relay can disrupt the fan's operation and may need replacement. Following this, test the fan motor directly by applying power to it; if the motor fails to spin, it likely requires replacement. Additionally, ensure that the temperature sensor is functioning correctly, as it plays a crucial role in signaling the fan to activate when the engine reaches a certain temperature. Don't overlook the wiring and connections; inspect them for any signs of damage or corrosion that could impede power delivery to the fan. Finally, using a diagnostic scanner can help identify any error codes related to the cooling system, providing further insight into the underlying issue. By methodically following these steps, you can effectively diagnose and address the radiator fan problem in your vehicle.

What are the common causes for the radiator fan not working in a 2004 Mercedes-Benz G500?

When dealing with a non-functioning radiator fan in a 2004 Mercedes-Benz G500, it's crucial to understand the common problems that could be at play. One of the primary culprits is a faulty fan motor, which can prevent the fan from operating altogether. Additionally, a blown fuse in the fan circuit can disrupt power flow, rendering the fan inactive. Another potential issue is a defective temperature sensor, which may fail to signal the fan to engage when the engine reaches a certain temperature, leading to overheating. Wiring issues can also be a significant factor; damaged or corroded connections can impede the electrical flow necessary for the fan's operation. Lastly, it's important to check the coolant level, as low coolant can cause the engine to overheat, which may affect the fan's performance. By systematically examining these areas, DIYers can effectively diagnose and address the radiator fan issue, ensuring the vehicle's cooling system functions optimally.

How urgent is it to repair the non-working radiator fan in a 2004 Mercedes-Benz G500 to prevent overheating and potential engine damage?

Repairing the non-working radiator fan in a 2004 Mercedes-Benz G500 is an urgent matter that should not be overlooked. The radiator fan is essential for maintaining optimal engine temperature by dissipating heat generated during operation. If the fan fails, the engine is at risk of overheating, which can lead to severe damage such as warped cylinder heads or blown head gaskets. Additionally, overheating can compromise other vital components, including the water pump and thermostat, resulting in a cascade of costly repairs. Ignoring the malfunctioning fan not only jeopardizes the engine's integrity but also poses significant safety risks while driving, as an overheated engine can lead to sudden breakdowns. Therefore, addressing the issue promptly is crucial for ensuring the vehicle's reliability and longevity, making it imperative for DIY enthusiasts to prioritize this repair.

You’ve got options with RepairPal

Whether you need a more accurate auto repair estimate or help finding a reputable shop in your area, we’ve got you covered.