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What can cause a cooling fan not to come on?

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What can cause a cooling fan not to come on?

Six things may prevent an electric cooling fan from coming on:

  • Defective temperature switch, coolant sensor or other sensor.
  • Engine thermostat is stuck OPEN (engine never gets hot enough to turn on the fan)
  • Faulty fan relay.
  • A wiring problem (blown fuse, loose or corroded connector, shorts, opens, etc.)
  • Bad fan motor.

What are the symptoms of a bad cooling fan relay?

Bad Cooling Fan Relay Symptoms

  • The engine runs hot or overheats.
  • The cooling fans don’t work.
  • The cooling fans keep running.
  • Warning lights.
  • Poor air conditioning performance.
  • Swapping Relays.
  • Measuring the Relay Coil’s Resistance.
  • Listening for Noises.

How do you diagnose cooling fan problems?

Symptoms of a Bad or Failing Cooling/Radiator Fan Motor

  1. Cooling fans do not come on. The most common symptom of a faulty cooling fan motor are cooling fans that do not come on.
  2. Vehicle overheating. Another symptom of a possible problem with the cooling or radiator fan motors is the vehicle overheating.
  3. Blown fuse.

Why is my fan not kicking on in my car?

If the fan doesn’t come on, you need to look for a blown fuse or breaker. In older cars, you might have a fusible link – this is wire within an insulated block of rubber. Try to grab the end and stretch it. If the wire stretches, the wire link could be broken and you’ll need to replace it.

What tells the cooling fan to come on?

The engine temperature should trigger the fan to turn on. It will also turn the fan off once the engine has cooled to under 200 degrees. You may have heard of a part called the radiator fan switch or temperature fan switch. This is linked to a thermostat and works much like your home’s HVAC system.

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 can I tell if a relay is bad?

You want to feel and listen for any clicks. If you feel and hear clicks, the relay works on one side – the side with the energizing circuit and coil. However, if there was no sound from the horn, the relay has a problem along the contact circuit.

Should radiator fan turn on when AC is on?

Both radiator fans should always run when the AC compressor is engaged. To check the temperature at which the fan comes on, turn the A/C off and keep the engine running until it reaches normal operating temperature. Most fans should come on when the coolant reaches about 200 to 230 degrees.

When should my radiator fan kick on?

about 200 degrees Fahrenheit
Your radiator fan should kick in at about 200 degrees Fahrenheit. If you notice your vehicle is overheating or at the very least running hotter than it normally does, listen for the fan to see if you can hear it.

How can you tell if your thermostat is open?

Start your car’s engine and allow it to idle. Look through the radiator filler neck to see if the coolant flows. At this time, it should not be flowing as your car has not reached the operating temperature to cause the thermostat to open. If you find the coolant is flowing, it means the thermostat valve is open.

What happens if your radiator fan does not work?

If the radiator fan fails or is not working properly your car can get serious damage, to repair which you have to spend thousands of dollars. Therefore, as soon as you feel that the radiator fan is not functioning rush to the mechanic and get it fixed. A radiator fan can stop working due to some reasons.

Where is the relay on a radiator fan?

The fan relay is often located in the engine bay’s fuse box, but the best way is to check your repair manual to find where it is located. Testing a 4 pin relay is often very straightforward. Remove the relay and give 12 volts to pin 30 and 85. Ground pin 86 and check if there is voltage coming out from pin 87.

What happens if your coolant level is low?

If your coolant level is low, there is a chance that you will get air in the system, and the coolant temperature sensor will not read the coolant temperature correctly. If the coolant level is low, you need to refill the coolant to optimum levels. Failing to do so could risk your engine becoming overheated and seized.