What Does a Cooling Fan Relay Do? The cooling fan relay is an electromagnetic switch that controls the power supply to the engine’s cooling fans. It ensures that the energy-intensive devices only run when needed, usually when the vehicle is immobile.

How much does a fan relay cost?

To get your cooling fan relay replaced, you will pay, on average, $80-$160, depending on the type of car you have and the mechanic’s fees. The labor should cost around $70, while parts should run you $10-$50.

What happens when a fan relay fails?

A faulty or broken relay cannot deliver power to the cooling fans. In turn, the unpowered fans won’t run, leaving the radiator to its own devices. Deprived of the helpful influx of air from the cooling fans, the radiator cannot remove as much heat as it usually does.

How do you test a fan relay on a car?

1. Look at the markings on top or side of the relay case and locate the two control circuit terminals, which connect to the relay’s coil, and the two power circuit terminals, which let electrical current pass to the fan. …
2. Connect the leads of an ohmmeter to the power terminals on the relay.

How do I know if my cooling fan is bad?

1. Engine Overheating. When the radiator fan isn’t functioning properly, it is not able to adequately cool down the car’s engine. …
2. Air Conditioner Function Diminished. …
3. Loud Noise Coming From Radiator Fan.

Can you drive without radiator fan?

Yes, technically your engine does not need a cooling fan to operate. … If the radiator does not have cool air blowing on it constantly, it will overheat eventually, so you’d need the perfect combination of weather and traffic to drive effectively without a radiator fan.

What causes radiator fan to stop working?

The most common reasons a radiator fan is not working are luckily due to a blown fuse, bad relay, or a broken wire. It can also be caused by a faulty coolant temp sensor, low coolant level or the fan itself can be damaged.

What causes a relay to fail?

In fact, the life of a relay is essentially determined by the life of its contacts. Degradation of contacts is caused from high in-rush currents, high- sustained currents, and from high voltage spikes. … Relays can also fail due to poor contact alignment and open coils.

When I turn off my car the fan keeps running?

It’s normal for some vehicles to have a fan run for a few minutes after the car is shut off, generally to keep the engine cool. However, if the fan is running for an extended period, the fan itself can become damaged due to overuse. … It’s possible you may have a module or relay failing in your car.

How does a relay work?

A relay is an electrically operated switch. They commonly use an electromagnet (coil) to operate their internal mechanical switching mechanism (contacts). When a relay contact is open, this will switch power ON for a circuit when the coil is activated.

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Can a relay drain your battery?

A failed ECM power relay can also cause a battery drain or dead battery. If the relay shorts it can leave power on to the computer, even when the vehicle is turned off. This will place a parasitic drain on the battery, which will eventually cause it to go dead.

Why are there two fans on a car?

The cooling fan in the engine compartment should turn on to pull air through the radiator and A/C condenser. On many vehicles, there may be two fans: a main cooling fan for the radiator, and a second fan for the condenser. Both fans should come on when the A/C is on. … The engine may also run hot and overheat, too.

Why are my car fans so loud?

Mechanical clutch driven fans are more likely to produce excessive fan noise, usually due to a worn clutch inside the fan assembly. … Worn bearings, bent or broken blades, and unbalanced rotating assemblies can cause a fan to screech, howl, or otherwise make noises it shouldn’t.

What does a fan relay Do HVAC?

In a blower motor, the relay supplies the power that allows the fans to circulate warmed air. Essentially an on/off switch, the blower motor relay’s reactions start and end the heating process in HVAC systems by controlling the flow of current between the power source and the motor.

Which relay is for radiator fan?

The cooling fan relay is normally located in either the underhood fuse and relay center or mounted to the electric fan assembly behind the radiator.

Can fan cause car to overheat?

Engine overheating: A bad radiator fan can cause the engine to overheat, especially at low speeds. If your car starts overheating, pull off the road as quickly as you safely can and turn off the engine.

Where is the cooling fan relay located?

The fan relay is usually located near the bottom of the engine compartment on a metal frame member. The metal acts as a heat sink to keep the fan relay cool.

How can you tell if a fan fuse is blown?

Remove the fuse from its holder. In some cases you may need a small screwdriver to unscrew the fuse holder cap. Look at the fuse wire. If there is a visible gap in the wire or a dark or metallic smear inside the glass then the fuse is blown and needs to be replaced.

Can a bad thermostat cause radiator fan not to work?

Broken Thermostat Thermostats are known to go bad and cause all sorts of cooling issues. … If this thermostat doesn’t open when the engine reaches the working temperature, the coolant will stay inside the engine block and the engine will start to overheat. This will result in the radiator fan not working.

How long does a relay last?

The electrical life expectancy of general purpose and power relays is generally rated to be 100,000 operations minimum, while mechanical life expectancy may be one million, 10, or even 100 million operations.

Why does a relay burn out?

The following causes are probable. If overvoltage is applied to the coil, the coil’s insulating film will be destroyed, and short-circuiting will cause high temperature. The color of the coil will change, and the resin around the coil will melt.

Why are relay used?

Relays are used where it is necessary to control a circuit by an independent low-power signal, or where several circuits must be controlled by one signal.

Can a relay short out?

Relay testing is a simple process, but don’t skip out on safety. … The wrong relay can cause a short or a power surge that can damage your vehicle’s electrical system. Handle the relay gingerly and try to avoid dropping it. If the relay is damaged internally, it can cause burning or melting of wiring.

Is relay a sensor?

The term “relay” is usually called a variety of devices, the switching contacts in response to a change in some input variable, not necessarily electric. … In fact it is the sensors that are connected to the relay and interacting with them according to a specific algorithm.

Which are the two types of relays?

• Relays are electrically operated switches. …
• Electromechanical relays have an electromagnetic coil and a mechanical movable contact. …
• Solid-state relays are solid-state electronic components that do not have any moving components, which increases their long-term reliability.

How do relays improve safety?

Safety Relays are devices that implement safety functions. In the event of a hazard, a safety relay will work to reduce to risk to an acceptable level. When an error occurs, the safety relay will initiate a safe and reliable response.