Table of Contents
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 check if a fan relay is bad?
The quickest way to tell whether or not the electric fan(s) are working is to start the engine. Then, let it reach normal operating temperature and then turn the A/C on. The cooling fan in the engine compartment, should turn on to pull air through the radiator and A/C condenser.
What happens if cooling fan relay goes bad?
One of the first symptoms commonly associated with a bad or failing cooling fan relay is an engine that runs hot or overheats. If the relay shorts or fails, it will not be able to supply the power for the fans to operate and keep the engine running at normal temperatures.
How do I know if my cooling fan switch is bad?
The best way to tell if your cooling switch is faulty is to listen to your engine while you drive. You know how your engine is supposed to sound, and if you notice that you don’t hear the fan as often as you normally do during your afternoon commute, you might have a failing switch.
How can I tell if my radiator fan is working?
A simple way to check if the radiator fan is working is to start your engine and turn the air-conditioning system (A/C) to the maximum speed. If the fan is spinning, then it means that the fan motor, fuse, wiring, and relay are all working properly.
What causes a fan relay to burn out?
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.
Where is the relay switch for a radiator fan?
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.
How do I know if my radiator fan motor is bad?
The first symptom or sign that something has gone wrong is that your cooling fan doesn’t come on at all. This is the most common symptom of a faulty cooling fan motor, but it may not be one you notice while driving your vehicle. If the motor burned out or starts to fail in any way, the cooling fans are disabled.
How much does a cooling 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 causes a cooling fan not to work?
ELECTRIC COOLING FAN PROBLEMS 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.).
How do you tell if a relay is burned out?
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.
How do relays get damaged?
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.
Can a relay overheat?
It is normal for the relay coil to be slightly hot during normal operation, but if the contacts are hot, it means that the service life of the relay has expired and should be replaced. Otherwise, the contact resistance of the contacts will be too large and lead to line failure (excessive voltage drop).
How do I know if my relay module is working?
How to test a relay Keep the multimeter in the continuity check mode. Check for continuity between the N/C contacts and pole. Check for discontinuity between N/O contacts and the pole. Now energise the relay using the rated voltage. Now check for continuity between N/O contacts and pole.
Does a relay click when it’s bad?
If your starter relay has gone bad, the electrical signal will never make it from the battery to the starter motor. 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.
Why does my engine cooling fan keep running?
This is normal in many vehicles, such as BMW or Mercedes-Benz. The radiator fan may run up to five minutes and sometimes longer. Unless there is an electrical issue, it may stay on all the time until it drains the battery. Running cooling fans help cool down the engine even after you turn off the car.
