Only One Speed From Blower Motor. One of the most common symptoms of trouble with the blower motor resistor is when the fan gets stuck in one setting. … Various Airflow Settings Not Working. … No Air Coming From Vents.
How do I know if my blower motor resistor is bad?
- Only One Speed From Blower Motor. One of the most common symptoms of trouble with the blower motor resistor is when the fan gets stuck in one setting. …
- Various Airflow Settings Not Working. …
- No Air Coming From Vents.
What is the purpose of the blower motor resistor block?
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.
Why does my blower motor resistor keeps going bad?
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.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 do I test a blower motor resistor?
Place one lead of the Ohmmeter on terminal 1 of the resistor. Place the other lead on terminal 2 and check against specifications. If this circuit is open, showing infinity on the Ohmmeter, the blower resistor must be replaced. Move the lead from terminal 2 to terminal 3 and check this reading against specifications.
Why does my blower motor work sometimes?
When a resistor fails, the fan will often run only at higher speeds or the highest speed, no matter what fan speed is selected. … 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.
What would cause a resistor to burn up?
Burning of Resistor When a resistor has been overloaded with voltage exceeding its power rating, the resistor will become very hot to touch, darken considerably and possibly even melt or catch on fire.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. … A failed blower motor resistor can cause issues with the operation of the entire heating and air conditioning system.
Is there a fuse for the heater blower?The blower motor is powered by a fuse-like device called a relay. If your heater or air conditioner does not blow air through the vents, this could indicate that the blower motor fuse has probably blown. While replacement is easy, the exact location of your blower motor fuse may vary from vehicle to vehicle.
Article first time published onWhy does my blower motor fuse keep blowing?
Blown fuses 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.
What components should be checked if a blower motor resistor is found to be defective?
- Fan does not work at all, so no air comes out of the vents.
- Fan only works on some speeds and not others.
- Fan only works on the highest speed.
- Fan runs all the time and can’t be controlled with the fan switch.
- You see smoke coming out of the vents.
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 reset my blower motor?
- Step 1: Turn off the power to the furnace. …
- Step 2: Remove the blower compartment cover. …
- Step 3: Make sure the blower is completely cooled off. …
- Step 4: Locate the reset button. …
- Step 5: Press the button in (assuming that this is your issue and that the button has popped).
Why does my blower motor only work on low?
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.
Why does the blower in my car only work on high?
Most car manufacturers use a series of resistors to make the heater blower motor run at different speeds. And when one or more of these resistors burn out, you’re usually left with only one heater blower motor speed—high. … Remove the screws, and swap out the resistor module.
What does a final stage resistor do?
The final stage (or blower motor) resistor controls the speed of the blower motor in your heating & air conditioning system. Faulty resistors can cause a list of erratic issues, from the fan running when the car is off, to only having one fan speed available.
Can you test a blower motor resistor with a test light?
Unplug the blower motor and test for power using the 12-volt test light in the same manner as explained in Step 1. … If there is power indicated on high blower speed, but not low or mid range, the problem is the blower resistor.
What is blower motor 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 are the symptoms of a bad blower motor?
- 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 with a multimeter?
Using a multimeter set on the Ohm scale, use the positive lead and test the black wire. To check the purple wire for current, use your ignition key and turn it to the run setting, turn the heater power to full power and set the multimeter to DC power. If your meter reads “no current” the motor is no good.
How do you test a blower motor switch?
Test the switch. Plug the connector back in to the blower motor, and then trace the wire harness back to the connector closest to the blower motor switch, usually located under the dash. Disconnect the connector and set the multimeter to ohms.
Can a bad blower motor cause no heat?
Problems with Your Blower Motor or Blower Motor Resistor Your blower motor is the component that pushes air through your car’s heating or cooling system. Without it, there’s no circulation of air—hot, cold, or otherwise. … Both of these components can fail, resulting in the heating system simply not working.
How do you keep a resistor from overheating?
Resistive losses can be reduced by the choice of appropriate voltages. It is much better to feed a low voltage low current device like an LED from a low voltage, through a low value resistor, than from a high voltage through a high value resistor. With an LED the light output is the property of interest.
How do you fix a burnt resistor?
- Scarp the outer coating.
- Clean the burnt section of the resistor.
- Measure resistance from one end of the resistor to the damaged section.
- Again measure the resistance from the damaged section to the other end of the resistor.
- Add these two values of resistances.
Do resistors go bad?
Resistors rarely fail when the circuit is designed properly, but under overload conditions (such as the failure of a component elsewhere in the circuit that puts a high voltage across the resistor) resistors typically fail by becoming an open circuit (after becoming very, very hot to the point of incandescence).
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.
Why is my heater not blowing hot air?
The Furnace Is Blowing Cold Air First, check to make sure the thermostat is set correctly. You will want to make sure that the fan control is set to auto, and not ‘on’. If the thermostat appears set correctly, turn off your heater at the thermostat and check the filter. If the filter is dirty, replace it.
Why does my 5 amp fuse keep blowing?
5A Fuse on Circuit Board Keeps Blowing Check the compressor unit for any damage. If the compressor unit it can cause a fuse to blow. Check the wiring between the air handler and the consensus unit. If this wire has a low voltage capacity it could cause problems to the fuse.
