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How To Replace A Blower Motor Resistor

When it comes to your car, there are a lot of things that can go wrong. One of the most common problems is with the blower motor resistor (BMS). If this component fails, it can cause your car to stop working altogether. In this blog post, we will show you how to replace a BMS on a Ford Mustang. We’ll also provide some tips on how to troubleshoot and fix other electrical issues in your car. So if you’re ever having trouble with your car, be sure to check out this blog post for help.

What is a Blower Motor Resistor?

A blower motor resistor, also known as a resistor in series, is a component that suppresses current flow through the motor. When the voltage across the resistor reaches a certain level, it begins to divert current away from the motor, causing it to stop. This is why replacing a blower motor resistor is so important – if it fails, your heater will not work.

How do I replace a blower motor resistor?

If your furnace, air conditioner, or blower motor is not blowing as hard as it used to, it might be because of a resistor in the circuit. This type of component is usually easy to replace yourself, and here’s how:

1. Turn off the power to the unit. If you’re working on an electric furnace, turn off the breaker that supplies power to the furnace. If you’re working on an air conditioner or blower motor, turn off the breaker that powers those devices.

2. Remove any screws that hold the housing together. You’ll need access to all four screws in order to remove the housing Later there are usually two more hidden screws at either end of the housing that must also be removed before lifting out the resistor.

3. Once all screws are out, lift out the housing and examine it for damage. If everything looks good, replace the resistor with a new one using these steps: Loosen both ends ofthe old resistor by unscrewing them about 1/4 turn each (counterclockwise if looking from above). Push new resistor into one end ofhousing while holding onto other end; tighten screw at each end by turning clockwise (seen from above). Replace screws and reattach housing. Test unit before turning power back on!


Blower motors resistors are typically installed to protect the fan from overloading and damaging. Over time, these resistors can become old and broken, which could cause the blower motor to overheat and fail. In order to replace a resistor, first remove the screws that hold the cover in place. Once the cover is removed, locating the resistor will be much easier. Locate the three wires that go into the motor and unscrew them from their terminals. Next, unclip the resistor from its terminal and replace it with a new one. Reconnect all of the screws and reattach the cover.

Parts Required

Installing a new blower motor resistor can be a simple and inexpensive repair for your A/C unit. You will need the following parts:

– New blower motor resistor
– 6″ Extension Cable
– Flat head screwdriver
– Socket set
– Long nose pliers
– Wire cutters
– Tapping tool
– Soldering iron and solder
– Electrical tape


If your blower motor resistor is going out, it’s easy to replace. Here are the steps: 1) Unplug the power to the furnace and turn off all heat sources. Note: If your blower motor resistor is located on a circuit breaker box, wait until after you’ve turned off all other circuits before unplugging it. 2) Remove the coverplate on the furnace using a flathead screwdriver. On some models, there are two screws at the top and two screws at the bottom of the coverplate. 3) Locate and remove the blower motor resistor. 4) Solder in a new resistor according to manufacturer’s instructions. 5) Replace the coverplate and screws. 6) Plug in the power to the furnace and turn on all heat sources. 7) Check for proper operation of the blower motor by checking voltage at terminals A and B on your furnace model number label (usually marked near main burner).

Tips for replacing a blower motor resistor

If your home’s central air conditioning system is old and struggling to keep up with the summer heat, it might be time to consider replacing the blower motor resistor. A blown resistor can cause the AC unit to stop working altogether, so it’s important to identify the problem and take action before things get too bad. Here are a few tips for replacing a blower motor resistor:

1. Verify that the AC unit is currently not working. If you’ve already replaced the power cord, transformer and fan coil, chances are that the blower motor resistor is also at fault. If your AC unit still powers on but doesn’t seem to be blowing cold air, then you can assume that your blower motor resistor is malfunctioning.

2. Unplug all of the AC cords from the wall and from any plugs near where you’re planning on removing the resistor. This will help limit potential damage if something happens while you’re working on the AC unit.

3. Turn off all of the lights in your home or building before beginning work on your AC unit. It’s easy for mistakes to be made in low light conditions, and an accidental electrocution could happen very quickly in a dark room.

4. Use caution when opening up an AC unit! Even if there are no live wires connected, high voltage currents can still flow through open circuits – potentially causing serious injury if touched! Always wear gloves, use a voltmeter to verify that there is no current