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.
Where is the blower motor resistor module located?
Locate the blower motor resistor. It can be found below the blower motor. In some vehicle’s you need to remove the glove compartment to access the blower motor resistor. Now that you’ve located the blower motor resistor, you’ll now need to disconnect the resistor from the housing and then remove the harness.
What are the signs of a failing 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.
What happens when the blower motor resistor goes out?
Power to the blower motor is fed through the blower motor resistor, so if it fails or has any issues power can be cut off to the motor. A blower motor without power will not be able to produce any air pressure, and as a result the heating and air conditioning system will be left with no air coming from the vents.
Does a blower motor resistor control the fan speed?
Blower resistors are resistors which are used to control the fan speed of automotive blowers. The fan speed can be changed either by switching the blower resistor resistance mechanically using a rotating lever, or electronically by the air conditioning system.
How do you replace a blower motor resistor?
- Step 1: Remove the glove box door, if necessary.
- Step 2: Disconnect the wiring harness and remove screws.
- Step 3: Remove and replace the blower motor resistor.
- Step 4: Tighten screws and reattach wiring harness.
- Step 5: Reinstall the glove box door.
Is there a way to test a blower motor resistor?
If you want to do a quick test of the blower resistor, you can check the resistance of each of the resistors with a multimeter as follows: set the tool to read ohms (a measurement of resistance) and connect one of its probes to the common output terminal of the resistor.
Does a blower motor resistor have a fuse?
A fuse is often located on the resistor board. The fuse only protects the low and medium blower speeds. High speed will still work if the resistor fuse is blown.
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.
How do I know if my heater resistor is bad?
If you try to increase the air pressure and you feel no difference in the pressure blowing, then your blower motor resistor may be failing. A damaged blower motor resistor will work on one fan speed which may not be enough to keep the inside of your car cool or warm enough.
Is there a fuse for 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.
How long do blower motor resistors last?
The blower motor resistor is designed to last for the car’s lifespan. In most cases, these resistors will wear out long before the car does. Usually, the wear that the blower motor resistor has is due to the constant use that it gets and the heat that it is exposed on a regular basis.
How do you test a resistor?
Can a bad blower motor cause no heat?
Problems with Your Blower Motor or Blower Motor Resistor Without it, there’s no circulation of air—hot, cold, or otherwise. The blower motor resistor is the part that controls the fan speed of the blower motor. Both of these components can fail, resulting in the heating system simply not working.
What does the blower motor resistor control?
Blower Motor Resistors (BMR) control the electrical current flowing from the fan switch to the blower fan, which allows the motorist to set the fan at different speeds.
How do you test a bad blower motor?
- Use voltmeter or ohmmeter to check for a blown fuse. If you find one, replace it.
- Start car and see if blower motor works.
- If the circuits are in good repair but the blower motor keeps blowing fuses, replace the blower motor [source: You Fix Cars].
How do I know if I need a new blower?
- Poor or Airflow from Air Vents. This will be the first and most obvious sign your blower motor has a problem.
- No Airflow At All From Vents.
- Skyrocketing Energy Bills.
- Strange Noises When You Turn on the Heat.
- Overheating Blower / Weird Smells.
How do you test a blower motor on a car?
Turn off your vehicle, set your multimeter to Ohms, and check for resistance between the blower’s positive and negative terminals. You may also turn the car key to run without starting the engine, put the cooling system at full blast, and check for DC voltage. If none of these produces a reading, the blower is bad.
Why do blower motor resistors fail?
In most cases, the blower fan resistor is failing either due to overheating or corrosion. If the blower fan fails, your car will not blow any forced air. However, sometimes the problem can be with the blower motor itself. This is especially apparent when you have replaced the blower fan multiple times.
Where is a blower motor located?
For most furnaces, your blower motor will be located in the base of the unit next to the air filter. For most ACs and heat pumps, it will be located inside the air handler (i.e., the indoor unit). It’s also possible that certain units may share a blower motor in the air handler—typically with an AC and furnace.
Where is the AC heater blower motor resistor?
It’s located inside the dash, often on the opposite side of the steering wheel or inside the engine compartment on the firewall. A blower motor resistor or a blower motor control module is the part that controls the speed of the blower motor.
What does a blower motor 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.
Why does my blower motor only work on high?
When a blower resistor fails, the highest fan speed usually is the only one that still works because it essentially bypasses the resistor and receives the maximum amount of voltage. When the resistor is working, it reduces the amount of voltage going to the lower fan speeds so the fan runs slower.
How do you test a blower motor control module?
How do I know if my heater fuse is blown?
You can quickly determine by checking resistance with a multimeter. A good fuse will have nearly zero ohms of resistance, if the fuse is blown there will be no reading.