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

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

Here are some of the warning signs of a bad heater blower motor resistor:

1. Fan does not work at all, so no air comes out of the vents.
2. Fan only works on some speeds and not others.
3. Fan only works on the highest speed.
4. Fan runs all the time and can’t be controlled with the fan switch.
5. You see smoke coming out of the vents.

Can a blower motor resistor work intermittently?

Intermittent Operation When the resister of the blower motor starts to fail, the motor operates only intermittently. The higher current can make the jump across the resistor contacts that are going bad and get the blower motor to engage.

How can you tell if a resistor is bad?

How to Know If Resistors Are Good or Bad

1. Turn off the power running through the circuit containing the resistor you need to test.
2. Look at the color bands around the barrels of the components for the code to determine resistor values.
3. Check resistor values with the color codes.

Why does my blower motor work sometimes?

The fan switch may be at fault, but a more likely reason is that a blower motor resistor that controls the voltage going to the blower has packed it in, resulting in only one speed remaining operable – usually the highest speed. …

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 only 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 happens when a resistor fails?

When a resistor breaks down, current typically flows through the burnt resistor without any resistance and thereby passes unchecked. Other components in the circuit may become damaged from the excess current flowing through.

Can a blower motor resistor fail in a BMW?

If the resistor isn’t working properly, then you’ll experience concerning and inconvenient symptoms in your BMW’s cabin. While blower motor resistor failure isn’t unique to BMWs, they still tend to experience them more than some other vehicles.

Where is the blower motor on a BMW E36?

Introduction. The Heating Ventilation and Air Conditioning (HVAC) blower motor is located at the top of the airbox under the black cowl cover at the base of the windshield. It provides airflow over the heater core to generate heat in the winter and over the evaporator to provide air conditioning in the summer.

Why is my HVAC blower not working properly?

Many problems with the HVAC blower are misdiagnosed and may, in fact, involve a much simpler solution. For example, if, on manual climate control equipped cars, the fan only runs on the highest setting the blower motor resistor pack is the cause. Replacement of the resistor pack is relatively simple.

Where is the resistor pack on a blower motor?

For anyone that has a blower motor that only works on high speed you may have a faulty resistor pack. The following is how I replaced mine. The resistor pack is located just to the right of gas pedal of left hand drive vehicles. In order to get to the pack, you must remove the pedal cover.