Full Answer
What are the signs of a bad blower motor relay?
What are the symptoms of a bad blower motor?
- Weak airflow. This is one of the first signs of a bad blower motor that people tend to notice. …
- Noises. Have you noticed any unusual noises coming from your vehicle’s HVAC system? …
- Smoke or smells.
Is there a relay on the blower motor?
The blower motor relay is located by the blower motor or in the relay panel. The defective Blower Motor Relay is disconnected or the relay is pulled out of the socket. The socket or connection is checked for damage. If there is no damage the new Blower Motor Relay is installed.
What does a blower motor relay do?
The blower motor relay is what cuts on the blower to release the cold air into the cabin of the car. When you turn on the switch in your car to activate the air conditioner, the blower relay will turn on and release the power needed to turn on the blower fan. This part of your car is only used when the air conditioner is turned on.
How to test if HVAC blower motor is bad?
There are 5 main bad furnace blower motor symptoms to look for:
- Weak airflow coming from the vents. Weak airflow can be an indicator of other problems too such as used up air filters but problems with the motor are a likely ...
- Fully clogged vents. This too can be caused by other issues but is a common symptom for an inoperable blower motor as well.
- Weird sounds. ...
- A high energy bill. ...
- Overheating. ...
What does blower relay do?
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.Apr 1, 2019
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 a relay do in HVAC?
HVAC relays open or close circuits to turn equipment on and off. Also known as control relays, these magnetically operated switches are commonly used in fan motor operations such as air conditioning, heating, and ventilation systems.
What does a blower relay do in a furnace?
Gas Furnaces and Air Handlers use a fan relay to switch the blower motor ON and OFF. The fan circulates the warm or cold air inside the home. Most furnaces and air handlers using a two-speed motor, a high speed for cooling and a lower speed for heating.
What happens when a blower motor relay goes 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.Jan 4, 2016
How much does it cost to replace a blower motor relay?
between $73 and $83The average cost for blower motor relay replacement is between $73 and $83. Labor costs are estimated between $36 and $46 while parts are priced at $37. 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.
How do I test my HVAC fan relay?
0:211:38How To Test HVAC Fan Relay | HD Supply - YouTubeYouTubeStart of suggested clipEnd of suggested clipSet your meter to the lowest resistance level. And you should read approximately 70 80 ohms ofMoreSet your meter to the lowest resistance level. And you should read approximately 70 80 ohms of resistance. We're showing 79 it's good now between the other side five and six should show closed two.
How does thermostat relay work?
The two transformers provide the energy that the thermostat uses to connect the different relays. The relays in turn, turn on the energy to the fan and the air conditioning or the oven.
What is the difference between a contactor and a relay?
A contactor joins 2 poles together, without a common circuit between them, while a relay has a common contact that connects to a neutral position. Additionally, contactors are commonly rated for up to 1000V, while relays are usually rated to only 250V.Jun 18, 2018
How do I know if my furnace relay is bad?
Bad or Failing Blower Motor RelayBlower motor does not function. One of the first symptoms of a problem with the blower motor relay is a blower motor that does not function. ... Blown fuses. One of the first symptoms of a bad or failing AC blower motor relay is a blown AC blower motor relay circuit fuse. ... Melted relay.Feb 15, 2017
How do you replace a furnace blower relay?
7:2810:23AC Not Working?! Blower Motor RELAY not Working - YouTubeYouTubeStart of suggested clipEnd of suggested clipOn this side and two at the bottom you just want to make sure that when you install your relay atMoreOn this side and two at the bottom you just want to make sure that when you install your relay at the to go to the bottom. And that these four go here to the top. I just want to push in firmly.
What causes a blower motor to keep running?
If your fan limit switch is set to AUTO but the fan continues to run without ever stopping, you'll need to call a professional. Two problems that could cause your fan to run without stopping include: A bad fan limit switch that needs to be replaced. Bad thermostat wiring.
Why use a relay in a blower?
To bear electrical loads that are too large for traditional switches, relays are used. In certain situations, only the high-speed circuit can be in contact with the relay. If that’s the case, the blower can run at lower speeds but won’t perform when shifted to high. This could also be true of fully automatic programs.
Where is the blower motor relay located?
In general, the blower motor relay is in the under-hood fuse box or the under-dash fuse box. An exploded fuse can imitate the failure of relays. Many of the same signs will also occur with a faulty blower motor turn.
What does a blown fuse mean in an air conditioner?
A blown air conditioning unit blower motor relay circuit fuse is one of the first signs of a poor or failing AC blower motor relay. It can cause the blower motor fuse to blow if the blower motor relay develops a problem. As a result, it will hinder its ability to properly restrict and distribute power.
Why does my blower motor not work?
Because the relay is the switch that supplies the blower motor with current, if it fails internally, power will be cut off from the circuit of the blower motor. This means the motor will no longer run ...
What happens if a blower motor relay fails?
In most situations, if the blower motor relay fails, you will not have fan functionality. There are two main types of blower motors: single-speed and multi-speed. Single-speed means that the unit operates mainly with an on and off switch at a consistent speed. It will stop operating only once the desired temperature is reached.
What is a relay in a car?
Most of your vehicle accessories require a relay to operate – from your headlights to the cooling fan on the radiator. This also includes the blower motor that moves conditioned air out of its vents and into the cabin of the car. There will be at least one blower motor relay for your engine. The relay is a controller, and when you turn ...
Why do relays get hot?
They are exposed to high current loads, and when they develop issues, they can sometimes get hot. In severe cases, the relays can heat up to the point where their interior components and plastic housing will start to melt and burn. This sometimes causes damage to the fuse box or panel as well.
What is a blower motor relay?
The blower motor relay is the electrical switch that is used to supply the power for the vehicle’s blower motor. The blower motor is the component responsible for pushing air through the vents of your vehicle’s heating and air conditioning systems. Without it, the AC system will not be able to circulate any heated or cooled air.
Why does my blower motor fuse blow?
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. 3. Melted relay.
Why is my blower motor not working?
As the relay is the switch that supplies current to the blower motor, if it fails internally, then power will be cut off from the blower motor circuit, causing the motor to no longer function ...
Why do relays get hot?
Relays are exposed to high current loads and can sometimes get hot when they develop problems. In serious cases, the relays may heat up to the point where the interior components and plastic housing of the relay will begin to melt and burn - sometimes even causing damage to the fuse box or panel as well.
What happens if a blower motor does not work?
If the blower motor does not function, car fuses are blown, or relays are melting, you may have to replace the car blower motor relay. 1. Blower motor does not function. 2.
What is a 90-340 relay?
A 90-340 is a very common, versatile relay that many techs have on their truck. So, we will use it as an example. A relay is just a remotely controlled switch that opens and closes using an electromagnet. The electromagnetic portion that provides the opening or closing force of the switch is called the coil.
What is the portion of a relay that opens and closes called?
The portion of the relay that opens and closes can be called the switch, contacts, or points. These contacts can either be closed, meaning there is an electrical path, or open, meaning there is no electrical path.
How to find 90-340 relay coil?
Even though the coil is unmarked on most 90-340 relays, you can find it easily by locating the terminals with the small strands of wire connected. These two points connect through the electromagnetic coil.
What is the electrical portion of a switch called?
The electromagnetic portion that provides the opening or closing force of the switch is called the coil. Relay coils can come in many different voltages depending on the application, but in residential and light commercial HVAC, 24-volt coils are the most common. The portion of the relay that opens and closes can be called the switch, contacts, ...
