Lexus RX450hL Radiator Fan Isn't Working

Diagnosing the Causes of a Non-Functional Radiator Fan in Your Lexus RX450hL and How to Fix It

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Reviewed by
Bo Fader
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 Lexus RX450hL 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 Lexus RX450hL 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.

Troubleshooting Radiator Fan Issues in a Lexus RX450hL

When troubleshooting radiator fan issues in your Lexus RX450hL, start with the simplest solutions to avoid unnecessary complications. Begin by inspecting the 30A RDI FAN fuse located in the fuse box near the battery; a blown fuse is a common culprit that can easily be replaced. Next, check the functionality of the FAN relays, as these components control the operation of the radiator fan. If the fans are not running, it’s crucial to stop the hybrid system immediately to prevent overheating. Additionally, assess the coolant level and ensure there is no air trapped in the cooling system, as low coolant can lead to fan malfunction. If the fans are operational but you still experience issues, inspect for any blockages in the fan blades and consider the condition of the thermostat and water pump. By following this diagnostic approach, you can effectively identify and resolve radiator fan issues, ensuring your vehicle runs smoothly. If these steps do not yield results, seeking professional assistance may be necessary for more complex problems.

How to Diagnose and Fix Radiator Fan Issues in a Lexus RX450hL?

When tackling radiator fan issues in your Lexus RX450hL, it's crucial to understand the common problems that may arise. One frequent issue is a blown fuse, which can prevent the fan from operating. If you find that the fuse is burnt, replacing it with the correct size and type is essential, but be cautious; if it blows again, this could indicate a deeper electrical problem, such as a short circuit. Additionally, inspecting the fan's physical condition is vital; a fan that fails to activate when the AC is turned on may signal a malfunction in the fan itself or its control circuit. Overheating is another significant concern; if your engine temperature gauge is consistently high or you observe steam, this suggests that the radiator is not effectively cooling the engine. Other common culprits include a faulty starter relay, a defective fan motor, or issues with the engine control module (ECM) and wiring. To accurately diagnose these problems, consulting the wiring diagram can provide insights into the system's operation and help identify any wiring-related issues. By being aware of these common problems, you can effectively troubleshoot and resolve radiator fan issues, ensuring your vehicle runs smoothly.

Why is the Radiator Fan Not Working in a Lexus RX450hL?

When the radiator fan in your Lexus RX450hL is not functioning, it is crucial to address the problem without delay. A malfunctioning radiator fan can lead to overheating, which poses a significant risk to your engine's health and overall vehicle performance. Common culprits include a faulty fan assembly, a blown fuse, or issues with the coolant temperature sensor. Additionally, problems such as a bad fan motor or wiring damage can exacerbate the situation. Ignoring these symptoms can result in costly repairs and potential safety hazards on the road. Therefore, it is advisable to conduct a thorough inspection of the fan assembly, fuses, and relays, as well as check for any coolant leaks or air in the cooling system. By taking these steps, you can ensure your vehicle remains in optimal condition and avoid the serious consequences of an overheating engine.

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Lexus RX450hL Radiator Fan Not Working: Causes & Repairs