2003 Mazda MPV Radiator Fan Isn't Working

Diagnosing the Causes of a Non-Functional Radiator Fan in Your 2003 Mazda MPV and How to Fix It

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Reviewed by
Devin Cabugcal
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 2003 Mazda MPV 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 2003 Mazda MPV 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 steps should I take to diagnose the non-working radiator fan in my 2003 Mazda MPV?

To diagnose the non-working radiator fan in your 2003 Mazda MPV, begin by checking the fuse associated with the fan; a blown fuse is a common and easily fixable issue that can halt fan operation. If the fuse is intact, proceed to inspect the relay, as it plays a crucial role in supplying power to the fan. A malfunctioning relay may need replacement. Next, test the fan motor directly by applying power to it; if it fails to operate, the motor itself may require replacement. Additionally, examine the temperature sensor, which is responsible for signaling the fan to activate when the engine reaches a certain temperature; a faulty sensor can prevent the fan from turning on. Don’t forget to inspect the wiring and connections for any loose or damaged components that could disrupt the fan's functionality. If these steps do not resolve the issue, it may be time to consult a mechanic who specializes in automotive cooling systems for a thorough diagnosis and repair. By following this structured approach, you can effectively identify and address the problem with your radiator fan.

What are the common problems that could cause the radiator fan to stop working in a 2003 Mazda MPV?

When troubleshooting the radiator fan issues in a 2003 Mazda MPV, it's essential to understand the common problems that could lead to its failure. A faulty fan motor is often the primary culprit, as it can prevent the fan from spinning, resulting in engine overheating. Additionally, a blown fuse in the fan circuit can disrupt the power supply, causing the fan to stop functioning altogether. Another potential issue is a defective relay, which controls the power to the fan; if this component fails, the fan may not activate when needed. It's also important to check for broken fan blades, as damage can hinder the fan's ability to circulate air effectively. Furthermore, a malfunctioning coolant temperature sensor may fail to signal the fan to turn on at the right temperature, exacerbating overheating problems. Lastly, wiring issues can prevent the fan from receiving the necessary power, leading to operational failures. By systematically addressing these common problems, you can effectively diagnose and resolve radiator fan issues, ensuring your engine remains cool and operates efficiently.

How urgent is it to repair the non-working radiator fan in a 2003 Mazda MPV to prevent overheating and potential engine damage?

Repairing the non-working radiator fan in your 2003 Mazda MPV is an urgent matter that should not be overlooked. The radiator fan is essential for regulating the engine's temperature by ensuring that the radiator remains cool. If the fan fails, the engine can quickly overheat, leading to serious and costly damage such as warped cylinder heads or blown head gaskets. These issues not only compromise the vehicle's performance but can also result in extensive repairs that may require significant time and financial investment. Therefore, it is crucial to address any signs of a malfunctioning radiator fan immediately to safeguard your engine's health and avoid the risk of complete engine failure. Prioritizing this repair will help maintain the overall performance and longevity of your Mazda MPV, ensuring a safer driving experience.

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