Quick Answer: How Do I Know If My Cooling Fan Relay Is Bad?

Does the coolant temp sensor control the fan?

The sensor works by measuring the temperature that’s being given off by the thermostat and/or the coolant itself.

The temperature is then sent to the on-board control system.

As the control system receives the temperature from the CTS, it may trigger the cooling fan to either shut off or turn on..

Can a bad thermostat cause radiator fan not to work?

If the thermostat is stuck open (allowing coolant to flow) it can cause the engine to run cooler than normal so obviously the fan wouldn’t come on…..but not like the engine/coolant can be running too hot and the thermostat somehow effects the sensor reading or operation of the fan.

How much does it cost to fix a radiator fan?

Fortunately for you, the average cost of a radiator fan is not very expensive. The cost is typically between the range of $300-$400. The mechanic might charge you an extra $100-$200 for the labor involved. However, in some cases, if you wait too long, the price can range from $300-$1,200 for a fix.

Why does my radiator fan turn on and off?

To avoid a further rise of temperature, the fan induces air flow. The fan turning on is normal and a consequence of the hot coolant, not a cause. … The coolant may not be moving due to a water pump problem, blockage in the radiator or hoses, or a stuck valve, i.e., the “thermostat” in the coolant line.

Does a relay click when it’s bad?

If you hear or feel the relay click, the relay and its wiring aren’t the problem. But if it’s not clicking, the problem could be in the relay itself or in the wiring. … Actually, unless the relay has a diode in it, it won’t matter if the polarity is switched; the electromagnet will be energized regardless.

How can I tell if a relay is bad?

Symptoms of a Bad or Failing Ignition RelayCar suddenly stalls while operating. One of the most common symptoms of a failed ignition relay is a car that suddenly stalls while operating. … Car not starting. Another symptom of a faulty ignition relay is a no power condition. … Dead battery. A dead battery is another symptom of a faulty ignition relay. … Burned relay.

Should radiator fan run all time?

An electric fan SHOULD NOT run all the time. A mechanical fan WILL spin as long as the engine is running, but it will only ‘lock up’ when needed. If it has failed, it would be probably seized and locked up all the time.

Is there a fuse for the 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.

Why does my radiator fan not turn off?

A common problem vehicles experience is a cooling fan that doesn’t kick on and off when it’s supposed to. … The first is the fan relay, which due to age or corrosion will stop switching the fan on and off. The second is the fan switch itself, the sensor which tells the relay when to activate the fan.

Do both radiator fans turn on at the same time?

No they should cycle like that, one fan is for engine cooling the other is for A/C. … All cars run hotter with the ac on. You will find, a vehicle with 1 fan, will probably run all the time with the ac on, even from a cold start up.

How do you test a cooling fan?

The fan motor itself can be checked by using jumper wires. Unplug the wiring connector on the fan, and use the jumper wires from the battery to route power directly to the fan. If the fan motor is good, the fan should spin at normal speed when supplied with 12 volts.

What causes a fan relay to go bad?

Possible Causes of a Bad Cooling Fan Relay Common causes for relays going bad include: Overheating caused by the relay or a part mounted on or near the radiator.

How can I tell if my radiator fan is bad?

How to Check a Radiator FanDetermine whether your radiator fan is manual or electric. … To check an electric radiator fan, start the car and let it get up to the temperature where the fan normally kicks on.Use the volt meter to test if there is power to the wires. … Normal voltage for a radiator fan is around 12 volts.More items…

Should radiator fan run when AC is on?

Both radiator fans should always run when the AC compressor is engaged. Both radiator fans should always run when the coolant temperature sensor in the bottom tank of the radiator reaches about 212*F.

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. So, unplug the connector at the relay and repeat the check for power. If you get power, you’ve got a bum relay.