Blower motor running wide open after replacing resistor

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.

Why does my blower motor resistor keep blowing?

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 resistance should a blower motor resistor have?

According to the service manual, it must be around 4-5 ohms. In our case the ohmmeter shows open circuit, which means the resistor has failed. Sometimes, a blower motor resistor might fail due to problems with the blower motor itself.

How do you Ohm a blower motor resistor?
What we're going to do is we're set on ohms. Obviously both leads in the correct position once again I'll touch the leads together. Make sure you have continuity.

Why does my blower motor keep running?
So what happens sometimes is the blower fan off setting which is typically the lowest notch on that dial is set a little bit too low and it's too close to the room temperature.

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

  1. Blower 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 at all. …
  2. 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. …
  3. Melted relay.
  4. How do you 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.

    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.

    How does a blower motor resistor circuit work?

    The change in resistance controls the current through the blower motor, which in turn limits the speed that the blower motor spins at. When high speed is requested, the blower motor resistor is bypassed and the blower motor ground circuit is connected directly to ground.

    How do I test a resistor with a multimeter?
    And take a resistor and touch the multimeter probes to the resistor. You can touch any prob any side of the resistor. If multimeter doesn't show any resistance.

    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 I know if my AC 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.

    Can a resistor be intermittent?

    Resistors can fail open or short, alongside their value changing under environmental conditions and outside performance limits. Examples of resistor failures include: Manufacturing defects causing intermittent problems.

    What does it mean when a resistor is open?

    An open component is one whose resistance has dramatically increased. For the record, resistors tend to fail open more often than fail shorted, and they almost never fail unless physically or electrically overstressed (physically abused or overheated).

    Do resistors fail open or short?

    Resistor failures are considered to be electrical opens, shorts or a radical variation from the resistor specifications. The failure modes experienced vary with the type of construction. A fixed composition resistor normally fails in an open configuration when overheated or overly stressed due to shock or vibration.