• Home
  • What happens if your blower motor relay is bad?

What happens if your blower motor relay is bad?

Author of the blog (work in a car repair shop)
Ask Q

What happens if your blower motor relay is bad?

If the blower motor relay develops any sort of problem that hinders its ability to properly limit and distribute power, it may cause the blower motor fuse to blow. Any sort of electrical spikes or excessive current from a bad relay will blow the fuse and cut power in order to protect the system.

How do I know if my blower motor relay is bad?

If you have a faulty blower motor, you may experience low airflow from the vents, even when the fan is on high. There will be no air coming from the vents if your fan isn't working due to a bad blower motor resistor. Blown relay circuit fuses or melted relays are more serious signs of a bad blower motor relay.

What does the blower relay control?

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.

What causes blower motor relay failure?

In most cases, a blower motor resistor fails due to corrosion or overheating. Sometimes, the mechanical resistance to the motor rotation causes an excessive electric current that can overheat and prematurely damage the blower motor resistor.

How do I test a blower motor relay?

Connect a test light or multimeter to the ground (black lead). Turn the ignition key to the on position (engine off), and remove the relay. Using the probe, test all terminal sockets in the relay connector. Two of the four should have power.

How do I know if my blower motor relay is bad?

If you have a faulty blower motor, you may experience low airflow from the vents, even when the fan is on high. There will be no air coming from the vents if your fan isn't working due to a bad blower motor resistor. Blown relay circuit fuses or melted relays are more serious signs of a bad blower motor relay.

What causes blower motor relay failure?

In most cases, a blower motor resistor fails due to corrosion or overheating. Sometimes, the mechanical resistance to the motor rotation causes an excessive electric current that can overheat and prematurely damage the blower motor resistor.

How much does it cost to replace a blower motor relay?

The blower motor is operated by an electrically operated switch, called a relay. If the relay fails, the motor's fans will not blow conditioned air into your car. Fixing the relay usually costs around $50 to $80. So, if the blower motor relay fails, you could be left sweating or shivering.

Is there a fuse that controls the blower motor?

Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually under the dashboard on the passenger side.

Where is the blower motor relay fuse located?

Under the instrument panel, look under the glove box. On the right side of the fender wall you will find another fuse box. The blower motor fuse is easy to replace.

Will a blower motor work without the resistor?

Without any power, the motor won't run. As a result, the blower fan stays still and silent, and no air blows out of the vents. There are instances where a bad resistor will prevent the current from reaching the blower motor altogether.

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.

Where is the blower motor relay fuse located?

Under the instrument panel, look under the glove box. On the right side of the fender wall you will find another fuse box. The blower motor fuse is easy to replace.

How do I know if my blower motor relay is bad?

If you have a faulty blower motor, you may experience low airflow from the vents, even when the fan is on high. There will be no air coming from the vents if your fan isn't working due to a bad blower motor resistor. Blown relay circuit fuses or melted relays are more serious signs of a bad blower motor relay.

What causes blower motor relay failure?

In most cases, a blower motor resistor fails due to corrosion or overheating. Sometimes, the mechanical resistance to the motor rotation causes an excessive electric current that can overheat and prematurely damage the blower motor resistor.

How do I test a blower motor relay?

Connect a test light or multimeter to the ground (black lead). Turn the ignition key to the on position (engine off), and remove the relay. Using the probe, test all terminal sockets in the relay connector. Two of the four should have power.

How do I know if I need a blower motor or a resistor?

Signs of a Bad Blower Motor Resistor Loss of HVAC fan control (total or certain speeds) The fan only works on its highest speed setting. No air coming from vents. Intermittent or inconsistent fan speed.

Should you replace blower motor and resistor at the same time?

We do suggest that you replace the resistor at the same time. It may not be critical, but this will keep the system more uniform. The issue may even be related to the resistor. If you know that it is not related to the issue, then you do not have to replace it.

Why is my blower not working in my car?

Find the fuse associated with the A/C blower motor. If the blower motor fuse is still in-tact, your problem is located elsewhere. If the fuse is blown, simply replacing the fuse with an identical fuse of the same amperage rating could get your system working again!

Does a blower motor have a relay?

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.

What would cause my heater blower to stop working?

If little air is coming through the vents (hot or cold), then it could be because the blower motor for the fan or a switch or resistor that controls fan speed isn't working. Another cause might be that the electronically controlled “blend doors” that direct air flow are stuck or broken.

What does a heater relay do?

The electric relay in a furnace is responsible for relaying electrical power to the heating elements and the blower motor inside the furnace cabinet. The heating elements provide the heat to warm the air, and the blower motor sends this warmed air through the ductwork.

Does the blower motor resistor control heat?

The blower motor resistor is an electrical component that is a part of the vehicle's heating and air conditioning system. It is responsible for controlling the blower motor's fan speed.

Where is the best place to find the location of a blower relay?

The blower motor relay is generally located in the under-hood fuse box or in the under-dash fuse box. A blown fuse can mimic relay failure.

How many blower motors are in a car?

The number of blower motors in your vehicle depends on its climate control system. Some cars have one blower motor, but that may not be the case for some SUVs and vans. They may have two motors, one in the heater box and another in the vehicle's rear area.

What is the difference between blower motor and blower motor resistor?

The blower motor resistor is responsible for controlling the blower motor speed. In the past, this was done by varying the voltage supplied to the blower motor. In newer applications, the blower motor resistor is actually a solid state module that sends a varied signal to the blower motor.

Below you will find two interesting articles on a similar topic 👇

Why is my car heater not blowing air?

What relay controls the blower motor?

Tired of looking for a video for your question?

Video Answer below 👇

Were our answers helpful?

Yes No

Thanks so much for your feedback!

Have more questions? Submit a request

FAQ for the last Day

  • Why is my boiler not heating my radiators?
  • If your boiler works but the radiators are not heating up, then likely cause could be a faulty boiler pump or your central heating controls. If your boiler works but the radiators are cold, check that the thermostat or timer is working correctly.If your boiler works but the radiators are not heating up, then likely cause could be a faulty boiler pump or your central heating controls. If your boile...


  • Should I turn my boiler off if it has a fault?
  • If you spot a boiler leak you should switch off your boiler to make sure the electrics don't short circuit and to stop water damage in your home. Don't try and fix it yourself, get a professional Gas Safe engineer to deal with it.It is safe to turn a boiler off at the mains, it will just turn your boiler off. The main issue is that most boilers are designed to be on continuously, so it is not reco...


  • Why is my central air working but not the heat?
  • Problem #3: Heating system blows cold air The fan limit switch is faulty. Refrigerant levels are low (heat pump only) The reversing valve is bad (heat pump only) The outdoor unit is malfunctioning (heat pump only)No warm air delivery at all. If you turn your central heating system on and set it to the desired temperature but it doesn’t deliver any air, you’ll have to attempt to isolate the problem...


  • Do I need to press the reset button on my boiler?
  • If your boiler has stopped working, then you will have to reset it. In some cases, resetting your boiler might be all it takes to get it back up and running. However, the more likely case is that your boiler has shut down due to an underlying fault, or unsuitable conditions.To reset a boiler you’ll need to find and press the reset button. Now, not all boilers can be reset in the same way. Some mod...


  • Where is the reset button on the boiler?
  • The reset button is located on the boiler's display and will likely show a flame with a line crossed through it. You will only need to press the reset button for three seconds before the boiler resets and the display screen should change.Do all boilers have a reset button? All boilers have a reset button but its location and how to use it varies from model to model. If you can't see the button, th...


  • Why is my Worcester boiler not heating the radiators?
  • Worcester boiler problems with no heating can often be resolved quite easily. If there is a build-up of air or sludge in the system it could be the reason why you are not getting the most out of your radiators. This will need them to be bled which can be done with a radiator key without an engineer.Radiators not heating up Worcester boiler problems with no heating can often be resolved quite easil...


  • Why is my boiler not responding to thermostat?
  • Make sure you are programming your thermostat correctly and setting the temperature above the threshold in order to turn the heating on as when the temperature you set is too low, it may not trigger the heating to come on.Set your thermostat to a much higher setting than usual and give it some time to respond. Maybe the boiler isn’t responding because the temperature setting is too low to trigger...


  • Why are my radiators cold when the heating is on?
  • Why is one radiator cold when the heating is on? One cold radiator usually indicates that either there is air in the system or there is a stuck valve within that radiator. The thermostatic radiator valve (TRV), like the one pictured below, controls the flow of hot water to the radiator.Why is my boiler working but radiators are cold? If your boiler works but the radiators are not heating up, then...


Comments

Leave a Comment

<
Email us