How do I know if my cooling fan relay is bad?

Engine running hot One of the first symptoms commonly associated with a bad or failing cooling fan relay is an engine that runs hot or overheats. If you notice that your engine is running at higher temperatures than normal, that may be a sign that the relay is not functioning properly.

How do you test a fan relay with a multimeter?

Grab a multimeter and set it to Ohms. Touch the leads across the electromagnet coil pins and measure resistance. Anywhere from 50-120 ohms is OK. Out of range or open means a bad electromagnet coil winding and time for a new relay.

How do you check a relay?

The only tool required to check a relay is a multimeter. With the relay removed from the fuse box, the multimeter set to measure DC voltage and the switch in the cab activated, first check to see if there are 12 volts at the 85 position in the fuse box where the relay plugs in (or wherever the relay is located).

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.

How much does a cooling fan relay cost?

Radiator Fan Relay Replacement Cost – RepairPal Estimate. Labor costs are estimated between $27 and $35 while parts are priced at $32. This range does not include taxes and fees, and does not factor in your specific vehicle or unique location. Related repairs may also be needed.

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.

What does a bad relay sound like?

A faulty relay often produces an audible clicking sound when you turn your car. Contact a mechanic immediately if your car fails to start and you notice this sound.

Where is the relay for cooling 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.

Should fan be on auto or on?

Keeping your fan on AUTO is the most energy-efficient option. The fan only runs when the system is on and not continuously. There is better dehumidification in your home during the summer months. When your fan is set to AUTO, moisture from cold cooling coils can drip and be drained outside.

How do you test a radiator fan relay?

Open your hood and take some time to locate your fusebox, which is mounted in front of the passenger side of the firewall. Remove the top cover to expose your fusebox and relays, check your radiator fan relays and remove them. Inspect for any damage to the pins or the body of the relay, such as bubbling or melting.

Why is the cooling fan not working?

If you think the cooling fan isn’t working because your temperature gauge is indicating overheating , open the hood, start the engine, and let it idle for 15 to 20 minutes. If the fan comes on, you may have a bad temperature sensor or gauge .

Why is your radiator fan not running?

The most common causes when a radiator fan is not coming on is broken fuse, bad wirings, bad coolant temperature sensor, bad fan relay, or a faulty radiator fan . Here is a more detailed list of the most common causes of a radiator fan not coming on.

Why is the engine cooling fan not working?

The temperature sensor determines when the radiator fan comes on by reading the cooling system temperature. If the sensor isn’t working, your fan won’t come on because it won’t know that the temperature is hot enough to require activation, which can frequently lead to overheating.