Blower fan speed won’t budge?
You might need a blower motor resistor replacement.
A blower motor resistor is an electrical component that controls the speed of the blower motor — sending warm and cool air through your HVAC vents. If you struggle to maintain the right temperature in the cabin, a faulty blower motor resistor might be the culprit.
Read on to explore the tell-tale signs of a bad resistor, the replacement process, and costs.
This Article Contains:
- How to Know if You Need a Blower Motor Resistor Replacement?
- How to Replace a Blower Motor Resistor?
- How Much Does Blower Motor Resistor Replacement Cost?
- 3 FAQs about Blower Motor Resistor
How to Know if You Need a Blower Motor Resistor Replacement?
Listed below are common symptoms that signal a blower motor resistor failure:
- Fan stuck at one speed (low or high speed)
- Inconsistent or intermittent fan speed
- The blower motor doesn’t work properly on certain settings
- Low or no flow of warm or cool air from the AC vent
- Vent releasing excessive heat or smoke
- A foul smell of burning plastic or metal emanating from the vent
- The fan doesn’t turn on or off
Think you need to switch your failed blower motor resistor with a new one?
Let’s help you understand the process.
How to Replace a Blower Motor Resistor: Step-By-Step
The process for replacing a bad resistor might vary depending on your vehicle’s make and model. For instance, replacing a bad resistor in a Land Rover might be different from that of a Honda. That’s why it is best to leave the job to the experts.
Here’s how a mechanic will do it:
Step 1: Locate the Blower Resistor
The mechanic will first locate your blower motor circuit. In most cases, they must remove the glove box to access it.
Step 2: Remove the Resistor from its Housing
Next, they’ll unscrew the resistor from its housing, disengage the locking tab of the wiring harness connector (electrical connector), and detach the harness that secures it in place. Then, they’ll remove the faulty blower resistor by sliding it out from the HVAC housing.
Step 3: Install the New Resistor
The mechanic will place the new resistor in position, connect the wiring harness, and re-engage the locking tab of the wire harness connector. They’ll secure the new resistor in the HVAC housing with screws.
Step 4: Test the New Resistor
With the new resistor in place, the mechanic will check if it’s functioning properly. Finally, they’ll restore and secure the glove box in position.
So, what would you likely spend on a professional replacement?
How Much Does Blower Motor Resistor Replacement Cost?
You can get your damaged fan motor resistor replaced for anywhere between $50 to $150. This includes both resistor pack and labor costs. The cost can vary based on your vehicle’s make and model as well as your location.
Now that you know all about this car repair, let’s go over some frequently asked questions.
3 FAQs about Blower Motor Resistor
We’ve rounded up a set of common queries regarding the typical lifespan of an HVAC blower motor resistor, reasons for premature failure, and more:
1. How Long Does a Blower Motor Resistor Last?
The fan motor resistor is one of the sturdier parts of your car machinery, designed to typically last throughout the vehicle’s lifespan.
However, in certain cases, the resistor might unexpectedly fail sooner than it should. Regardless of why the heater blower motor resistor fails, you must ensure that it is replaced as soon as possible.
2. What Causes the Blower Motor Resistor to Go Bad?
Here are the possible reasons why your heater blower motor resistor might tap out sooner than its typical lifespan:
- Normal wear and tear: One of the most common causes of a faulty resistor is prolonged wear due to excessive use.
- Frequent airflow adjustments: Constantly changing the airflow speed setting can accelerate wear and cause the blower motor resistor to stop working altogether.
- Short circuit: A short circuit in the control circuit or the AC compressor might lead to blower motor resistor failure.
- Faulty electrical component: Malfunctioning parts such as compressor electromagnetic clutch, evaporator motor, or condenser motor can cause resistor failure. You may also notice a lit check engine light.
- Blown fuse: A smaller than required electrical current value of your AC fan fuse may lead to overloading of the compressor or a blown fuse in the air conditioning system. This might cause your blower motor circuit to shut down and the check engine light to come on.
- Corrosion: Prolonged exposure to air and moisture can corrode the resistor coils or lead to a short circuit, resulting in irreparable damage.
- Excessive heat: A clogged cabin air filter can cause overheating and lead to blower motor resistor failure. Additionally, worn or jammed bearings can make it harder for the blower motor to move (especially at high speed), causing the resistor coils to heat up and break down.
3. Can I Drive with a Damaged Blower Motor Resistor?
Although you can still drive your car with a faulty resistor, you might face the following issues:
- Driving discomfort: With the blower stuck at a single speed setting, you might be unable to maintain the desired temperature within the cabin and feel too hot or too cold during your car drives.
- Unsafe driving conditions: Your blower motor is important for windshield defogging and defrosting. Without control over the blower fan speed adjustment, you won’t be able to clear the fog or frost off your windshield in freezing weather. This can lead to reduced road visibility and dangerous driving conditions.
- Further damage to HVAC: Driving with a broken HVAC blower motor resistor can cause the blower motor to overheat and eventually burn out. This may cause additional damage to your air conditioning system components — requiring costlier car repair or replacement.
Breeze Through Resistor Replacement with AutoNation Mobile Service
Keeping the blower motor resistor in good condition is crucial for the trouble-free operation of your car’s HVAC system. If you notice any signs of deterioration in the resistor, you must immediately get it replaced to avoid any further issues.
Want to switch your failed blower motor resistor with a new one?
AutoNation Mobile Service can help!
We’re a mobile auto repair and car maintenance company offering upfront pricing and a 12-month, 12,000-mile repair warranty on all auto parts.
Contact us to get a blower motor resistor replacement or other auto repair services from your driveway.