Troubleshooting Tips for When Your Radiator Fan Keeps Running

AvatarByCarl Frisch

A radiator fan is a device in an internal combustion engine that helps to keep the engine cool by blowing air over the radiator fins. When the radiator fan keeps running, it means that the engine is not cooling itself properly and is running hotter than it should be. This can be caused by a number of things, including a faulty thermostat, low coolant levels, or a problem with the radiator itself. If this issue persists, it can lead to major engine damage if not resolved quickly. In order to diagnose and fix the problem, it is important to check the coolant levels first and then inspect and replace any faulty parts if necessary.

What Causes Radiator Fans To Stay On?

A faulty radiator fan can cause the fan to stay on even when it should be off. The most common causes of a radiator fan staying on are a bad fan motor, relay, or wiring issue. The radiator fan is responsible for cooling the engine by sucking in air and pushing it through the radiator to dissipate heat. Without the fan working properly, the engine can overheat and cause serious damage. If you notice your radiator fan staying on, it’s important to have it checked out right away.

What are the Symptoms of Radiator Fan Issues?

The most obvious symptom of a radiator fan issue is that the fan will stay on even when the engine is cold or not running. Other symptoms include a loud noise from the fan, irregular cycling between low and high speed, or no response from the fan when you turn on your car. If you experience any of these symptoms, it could be a sign that your radiator fan isn’t working properly and needs to be repaired or replaced.

What Can I Do To Fix My Car’s Radiator Fan?

When troubleshooting a faulty radiator fan, you should first check for power to see if the problem is with a wiring issue or if there is no power at all going to the motor. You can also test the fan motor relay to see if it’s functioning correctly. If all else fails, you may need to replace your radiator fan altogether in order to get it back up and running again properly.

How to Check for Power to the Radiator Fan Motor

In order to check for power going to the radiator fan motor, you will need an electrical multimeter or test light. Start by disconnecting the wires from the connector coming out of your car’s fuse box and connecting one side of your electrical multimeter/test light into one end of each wire in turn while keeping one finger on each lead wire at all times (to avoid electric shock). If there is power present then your test light/multimeter should light up indicating that there is power going through this wire leading into your car’s fuse box – if there isn’t then either this wire has come loose/broken or there isn’t any power flowing through this circuit leading into your car’s fuse box at all.

How to Test the Fan Motor Relay

To test if your car’s radiator fans are working correctly, check its relay switch as well as its motor and wiring system. A relay switch helps control how much current flows through an electrical circuit by opening and closing contacts inside its housing when instructed by an external signal such as a temperature sensor or coolant switch – allowing more current flow when needed (ie: when your engine starts heating up). To test if yours is functioning properly start by disconnecting both wires connected from this relay switch – then using another multimeter set them both up with continuity testing mode (or buzzer mode) and connect both probes onto each end of these disconnected wires – if they beep then this confirms that these contacts within this switch are functioning correctly but if they don’t beep then unfortunately they may need replacing in order for them work again correctly.

Automobile: Radiator Fan Keeps Running

The radiator fan is an important part of the cooling system in most automobiles, as it helps maintain consistent engine temperatures. If the fan runs continuously, it could cause problems such as overheating or even engine failure. There are several common problems that can cause your radiator fan to keep running, and understanding how to diagnose and fix these issues can save you time and money.

High Coolant Temperature Causing The Radiator Fan To Stay On

The most common cause of a radiator fan that keeps running is high coolant temperatures. If the coolant temperature rises too high, the fan will stay on in order to help reduce the temperature by drawing air across the radiator fins. To check if this is the issue, use a thermometer to measure the coolant temperature while the engine is running. It should be around 195F (90C). If it is higher than this, then you need to inspect for any other issues that could be causing this such as a faulty thermostat or blocked radiator fins.

Relay Fuse Malfunction Causing The Fan To Stay On

Another possible reason for a continuously running radiator fan is a malfunctioning relay fuse. This fuse regulates how much power is sent to the fan motor, so if it’s not working correctly then the fan will never shut off. You can test this by checking for continuity with an ohm meter or multimeter between each of the terminals on the relay fuse. If there isn’t any continuity then you’ll need to replace it with a new one.

Blower Motor Resistor Failed or Damaged Causing The Blower Motor To Stay On

If your blower motor resistor has failed or become damaged then it could also be causing your radiator fan to stay on continuously. This part regulates how much power flows through to your blower motor and if it’s not working correctly then your blower motor will run all day long until you turn off your car. You can test this by using an ohm meter or multimeter between each of its terminals and looking for any signs of damage or corrosion that may be causing it not to work correctly. If there are any signs of damage then you’ll need to replace it with a new one in order for your blower motor and radiator fan to work correctly again.

In conclusion, there are several common problems that can cause your radiator fan to keep running such as high coolant temperatures, relay fuse malfunctions and faulty or damaged blower motor resistors. Knowing how to diagnose and fix these issues can help save you time and money when dealing with car maintenance issues related to your cooling system.

FAQ & Answers

Q: What Causes Radiator Fans To Stay On?
A: Common problems that can cause a radiator fan to stay on include high coolant temperature, relay fuse malfunction, and a damaged or failed blower motor resistor.

Q: What are the Symptoms of Radiator Fan Issues?
A: Some of the symptoms of radiator fan issues include loud noises coming from the fan, the fan not running at all, or the fan running constantly.

Q: What Can I Do To Fix My Car’s Radiator Fan?
A: To fix your car’s radiator fan, you can check for power to the motor, test the fan motor relay, test the blower motor resistor, and check for a faulty temperature sensor.

Q: How to Check for Power to the Radiator Fan Motor?
A: To check for power to the radiator fan motor you should first turn off your car’s engine and disconnect the negative battery cable. Next, locate and remove the wiring harness connector from behind your vehicle’s dashboard near where your car’s heater core is located. Then use a multimeter to check for voltage between each pin in the wiring harness connector. If there is no voltage present then you may need to replace your vehicle’s fuse box or wiring harness connector.

Q: How to Test the Blower Motor Resistor?
A: To test a blower motor resistor, you should first turn off your car’s engine and disconnect its negative battery cable. Then locate and remove your vehicle’s blower motor resistor from underneath its dashboard or near its glove box. Next use a multimeter set on ohms scale to measure resistance between each terminal on its connector plug. If there is an open circuit or a reading higher than what is specified in its service manual then it will require replacement.

In conclusion, radiator fan keeps running is a very common issue that is faced by many car owners. It can be caused by a number of different factors including faulty relays, worn out fan blades or motors, faulty wiring, and other mechanical issues. If you are experiencing this issue with your car, it is best to take it to a qualified professional in order to have the problem diagnosed and repaired as soon as possible. By doing so, you can ensure that your car’s cooling system remains in good condition and runs efficiently for years to come.

Author Profile

Carl Frisch
Carl Frisch
With more than 30 years in the bicycle industry, I have a strong background in bicycle retailing, sales, marketing and customer service. I have a passion for cycling and a dedication to excellence. As a manager, I worked diligently to increase my capabilities and responsibilities, managing up to eleven mechanics (at Palo Alto Bicycles) and later as a working partner in my own store.

As the shop owner of Spoke n’ Word Cycles in Socorro, NM, the success of the mission was my responsibility, which I pursued passionately since we opened in 2003 through the spring of 2011. I am adept at managing owned and loan inventory, preparing weekly & annual inventory statements, and managing staff. The role as managing partner also allowed me tremendous freedom. I used this personal freedom to become more deeply involved in my own advancement as a mechanic, to spearhead local trail building, and advocating for cycling both locally and regionally.

As a mechanic, I have several years doing neutral support, experience as a team mechanic, and experience supporting local rides, races, club events. I consistently strive to ensure that bicycles function flawlessly by foreseeing issues and working with the riders, soigners, coaches and other mechanics. Even with decades of experience as a shop mechanic and team mechanic, and continue to pursue greater involvement in this sport as a US Pro Mechanic, and UCI Pro Mechanic.

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