DIY Recommended

Symptoms of bad Blower Motor Resistor

If the blower of your car has only 4 or 5 distinct speed settings, it is likely to use a simple electric resistor to control the speed of the fan. The resistor sets the electrical current limits so that the blower can operate at the right speed. If the resistor fails, the blower will only work in the selected speed settings in most cases.

There are also cases in which a blower motor of the car may not work.

Fortunately, you can check the condition of the part by blower motor resistor test. With just a multimeter, you can find out when it’s time to find another replacement.

Blower Motor Resistor Test

If you hear a blower fan running but can’t make it change its speed, you probably have a resistor problem. Here are some tips for testing the blower motor resistor:

  1. Start by looking at the blower fan resistor. The repair manual can tell you its placement according to the model and design of your car is.
  2. Check out the resistor visually. Look for obvious signs of rust and burns from overheating.
  3. Check the electrical resistance of each terminal resistor with a multimeter. Set up an ohms reading device (resistance measure) and connect one of its probes to the resistor’s common output terminal. Use another probe to measure the resistance between the terminal output and each input terminal of the resistor. Measure the resistance between one pair terminals at a time.
  4. If any of the points indicate constant resistance, the blower motor resistor fails. Endless reading defines an open circuit.
Blower Motor Resistor

Be careful when handling a blower resistor. As electric currents pass through the resistor for a long time, this device can create high temperatures – enough to heat your fingers or worse.

What is the Blower Motor Resistor?

The blower motor resistor is usually located outside the heat box or HVAC plenum that transmits air into the internal space. It is generally installed in HVAC control cables somewhere between the blower control knob and the blower motor.

Blower Motor Resistor

The resistor controls the blower motor’s fan speed and changes the air pressure generated by the blower fan movement. It does this by controlling the electric motor that powers the motor.

The function of the Blower Motor Resistor

The resistor restricts current, thus reducing the power output to control the blower motor speed setting.

More Current = More Speed

Less Current = Less Speed

The blower motor ensures that the right amount of power reaches the car, turning the fan at the right speed to blow air from the HVAC system to the chamber.

Blower Motor Resistor

It is also important to note that most cars have a circuit that exceeds the resistor when the blower motor is at high speed. In this case, the battery power is sent directly to the Blower motor.

Many modern cars have a mini-computer, called a blower motor control module, instead of a traditional resistor.

What Are the Signs of a Bad Blower Motor Resistor?

Every time you play with your car’s air-conditioning system or heating system, you change the current flowing through the blower motor resistor on the way to the blower motor.

A malfunctioning or failing motor resistor interferes with the proper operation of the heating and air system. The most common symptoms include:

  • The blower fan stands on a single speed setting.

A resistor can vary between speed settings depending on user preferences. However, resistor failure can cause the speed to stick to a single speed setting.

While the blower motor is still running, you cannot change its speed. It can be unpleasant in situations where you want to adjust your car’s internal temperature to a comfortable level.

A blower confined in a high-speed environment will always blow you up in hot or cold air when you don’t need it, while a one stuck in a low-key environment can be just as frustrating.

  • Blower fan cannot access specific speed settings.

In some cases, a failed resistor may set more than a one-speed setting. However, it may lose the ability to reach certain speeds. A blower motor will work well in the available settings, but it won’t work well if you choose a disabled speed setting.

Blower Motor Resistor

This sign is not limited to a bad blower motor resistor. A broken blower motor switch can also stop the blower from turning to specific speed settings. If your blower motor cannot switch to a certain speed, check both the resistor and your dashboard switch.

  • No air from vents

In most cases, due to the presence of the bypass circuit, the blower motor will continue to operate at high speeds with a failed resistor.

However, there are situations where a default resistor will prevent the current from reaching the blower motor ultimately. Without power, the motor will not work. As a result, the blower fan remains quiet and still, and there is no air coming out of the vents.

This symptom may also appear from a failed blower fan or several other issues. If the blower motor resistor test clears the resistor and wiring, the problem may lie in the fan’s motor.

Causes of Bad Blower Motor Resistor

Resistors go through rough situations. They always have electricity flowing between them, and the voltage supply can change dramatically as the car owner adjusts the power of the fan blower.

The most common reasons for the failure of a blower motor resistor can include:

  • Rust from prolonged exposure to air and moisture.
  • Overheating – if the motor finds it difficult to move due to the bearings’ malfunctioning, it can raise the resistor’s temperature to dangerous levels.
  • Normal wear out with time and usage.

 What is the cost of replacing a Blower Motor Resistor?

Blower Motor Resistor

You can still drive your car despite the fault of the blower motor resistor. However, you will probably find it uncomfortable if you are unable to change the blower’s speed.

Depending on the manufacturer and model, the blower motor resistor can go anywhere between $3 and $335 at The Auto Parts Shop. Replacement parts come in individual units, two sets of resistors, or a blower motor resistor kit.

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Causes and Signs of Bad Transfer Case

The transfer case is one of the essential components that differentiate the all-wheel-drive (AWD) and four-wheel drive (4WD).  Driving all four wheels provides higher traction, which improves performance in rugged terrain.  It is done by the transfer case, which allows the ability to move to the front and back wheels.

When you have a damaged transfer case, you will find that you may have a problem or cannot switch to AWD or 4WD.

So let us discuss the symptoms that you may experience when this component fails.

Symptoms of Bad Transfer Case

The transfer case is supposed to have delayed the vehicle’s life — but that did not always happen.  Here are the most common signs you may come across  when dealing with a bad transfer case:

  • Issues while changing gears

One sign of a bad transfer case is when you have trouble rotating between gear ranges.  Although the problem may arise from a different cause, such as a low fluid level or a damaged connection, it indicates the internal transfer case failure.

transfer case

However, before you think something is wrong, make sure you follow the instructions (in your master’s manual) for handling the transfer case.  Before switching to a four-wheel drive, the vehicle must be stopped and the transmission set to neutral. Contrarily, you will hear a cracking noise when trying to change gears.

  • Problem staying in 4WD

Another common problem is the transfer case in 4WD.  The issue may appear due to external influences (e.g., a problem with the differential or the driveshaft), or it may be due to the internal transfer case’s concern.

  • 4WD will not engage or disengage

There are many reasons why a 4WD car system will not engage or disengage.  The issue may be due to anything from operating an incorrect rotation on the front axle to an electrical error in the control system.

It is also possible that the transfer case has internal problems.

  • Greasy puddle directly under Transfer Case

The one and the only reason behind the formation of a greasy puddle under your car is a “leakage.”

And this leakage could be in a transfer case.

transfer case

Ensure the leak is coming from the transfer case by lifting your car and checking it visually.  It is easily recognizable in the back part of the transmission or transaxle assembly.

  • Growling, grinding, or humming noises

Another sign of trouble in your car is the presence of strange noises that usually do not occur.  Strange noises can be disturbing and alarming, and they almost always indicate that big problems are right in the corner.

If you hear a growling, grinding, or humming sound that changes with the vehicle’s speed, it may come from a transfer case.  The cause can be a low level of fluid or a mechanical problem, such as loose chain, poor bearings, or damaged gears.

  • Illuminating 4WD Warning Light
transfer case

Some cars have a “four-wheel-drive” message (or something similar) that appears on the steering wheel when there is a problem with the system.  Other vehicles will allow the 4WD light to illuminate the track to indicate a problem, which may be a poor transfer case.

Causes of an Inadequate Transfer Case?

Often, a transfer case will fail due to a low level of fluids(caused by leaks), lack of maintenance, or normal wear.

It is important to deal with fluid leaks quickly to avoid damaging the case.  Frequently changing the transfer case fluid is also important.  

Faulty Transfer Case or Transmission Issues?

The transfer case is a component of your vehicle’s drivetrain, just like transmission – and they both have their functions.  Despite this, symptoms of transmission failure may resemble those of poor transfer case.  It can sometimes lead to confusion for car owners trying to repair their car themselves.

To avoid any confusion, it is a good idea to have a car inspection from a professional if you suspect a transfer case problem. They will have the proper tools (and years of experience) to properly inspect your vehicle.

Can transmission be damaged with a bad transfer case?

There are cases where a transfer case’s failure can damage other parts of your vehicle, including transmission.  It is always advisable to address any known issues as soon as possible to avoid additional problems.

transfer case

Transfer Case

As previously mentioned, the transfer case is found on vehicles with AWD or 4WD power and allows drivers to switch to these operating modes.

  • 4WD Transfer Case

A typical 4WD transfer case is located behind the transmission, powered by a transmission output shaft, and works very well as a second transmission.

Most 4WD transfer cases have four operating modes:two-high, neutral, four-low, and four-high.  Because drivers only do 4WD when needed, this type of system is called “part-time” four-wheel drive.

The gear unit you want can work with a lever, engine vacuum, or in-vehicle electronics.

  • AWD Transfer Case

AWD systems are distributed to all four wheels without any input from the driver.  Most modern SUVs have AWD and a front-wheel drive-bias layout.  Vehicles with this design have a transaxle instead of a transmission.

The transfer case mounts to the transaxle side and distributes power to the rear differential and one of the front CV axles. You may also hear that people refer to this type of transfer case as part of a power transfer unit (PTU) or something similar.

Some cars have AWD and a rear-wheel-drive scale.  With this design, the transfer case is very much like the one found in a 4WD vehicle. The main difference is that the transfer case does not have multiple gear ranges for the driver to choose from.

That is why this type of setup is also known as full-time 4WD.

If you are looking for transfer case part types, visit The Auto Parts Shop.

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Symptoms of Clogged catalytic converter

Today, more than 90% of cars run on internal combustion engines (ICE) – and this type of engine can stay here until electric vehicles are fully adopted.  However, this situation can also create harmful toxic chemical compounds that harm the environment. To combat these harmful emissions, car catalytic converters come to rescue. They use precious metals to convert poisonous gases into non-hazardous substances.  Due to the increase in global environmental awareness, this exhaust system component is considered an important invention in the history of automobiles.

Catalytic converters help combat harmful emissions by using precious metals to convert toxic gases into non-hazardous substances.

Symptoms of Clogged catalytic converter 

A clogged catalytic converter is not the same as a chemically worn or damaged as it creates excess exhaust pressure.  Such blockages prevent the engine from “breathing” properly because it restricts exhaust flow – which can further create engine performance problems.

Signs of a clogged catalytic converter:

  • Illuminated fault indicator light

The check engine light reflects you that “I need to see a doctor.” It alerts you to some problems that can make the performance of your engine inadequate and inefficient.

Car Catalytic Converter

The control engine lighting indicates various reasons.  It is suggested to hire a mechanic to diagnose the issue after seeing this warning.

  • Difficulty in starting and stopping the engine

Excessive exhaust pressure can suffocate and cause the engine to stall.  If it gets too congested, you may find your motor running and idle for a few minutes, only to die.

  • Less Fuel-saving and lower engine performance

A clogged catalytic converter prevents your engine from breathing properly.  It can cause a lack of acceleration and overall performance.  Also,  there is a decrease in fuel savings.

  • Unsuccessful emission test

Clogging can cause the inspection engine to burn out, causing you to pass the emission test in many places.  If a clogged cat is detached from the inside, it is unlikely that your car will pass the exhaust gas emission test.

As mentioned earlier, clogging can even lead to the fragmentation of catalyst materials.  If you suspect this damage level, knock the catalytic converter down and listen to the noisy sounds.

Car Catalytic Converter

A clogged catalytic converter can cause the test engine to burn out and cause you to pass an emission test.

Methods of diagnosing car catalytic converter failure

An experienced mechanic will detect a clogged converter by temporarily removing the oxygen sensor or open the exhaust pipe.  If the engine’s performance improves, the catalytic converter is more likely to be the component causing the problem.

You can check the structure of the converter for harmful damage while passing over road debris.

Test for back pressure

Measuring backpressure is another way to confirm your suspicion. All you need is a low-pressure gauge or a kit that tests the primary pressure.

For accurate readings, use a digital manometer or a pressure gauge with different units of measurement.

Car Catalytic Converter

In case your engine has a secondary air injection system, you can disconnect the control valve and install your pressure gauge.  However, for accurate results, connect the control valve to the exhaust system before the converter.

You can also drill a hole along the exhaust pipe to install the pressure gauge.  It is the best option for an old car, where O2 can get damaged.

Ann idle vehicle’s backpressure may vary depending on its year of manufacture, a model of manufacture, and type.  Typically, an idle engine should have a maximum of 1.5 PSI.  Of course, some machines can be upgraded, but the basic rules are 1.5 PSI and below.

When the car is rotated at 2000 RPM and stable at 3 PSI or lower, you probably won’t have problems with your catalytic converter.  If it is variable or exceeds 3 PSI despite having a stable RPM, this is a good indication that the back pressure is increasing.

Resetting the engine increases the pressure, which is normal.  However, at a stable RPM, an abnormal increase in pressure may indicate a possible strain.

Other methods of checking back pressure

You can check the pressure with a vacuum gauge.  Connecting the manometer to a collector vacuum source is much easier than joining the scale to the exhaust.

Car Catalytic Converter

Another way of checking the backpressure is by observing the scanning tool and considering parameters such as the versatile absolute pressure (MAP) and the calculated load.

Replacing or repairing a catalytic converter

The clogged catalytic converter needs replacement.  While catalytic converter cleaner claims the same but you can’t believe everything you read.

Working of the catalytic converter 

The catalytic converter reduces the emissions from the engine using a chemical reaction. There are two main sections. The first is a catalyst with a combination of platinum and rhodium.  It works by breaking down nitric oxides (NOx) into nitrogen and oxygen molecules.

As the exhaust gas moves further, it passes through a second catalyst, a combination of platinum and palladium.  It is where double oxidation takes place – carbon monoxide (CO) and hydrocarbons (HC) are broken down into non-harmful molecules such as carbon dioxide (CO2) and water (H2O).

Car Catalytic Converter

Oxygen (O2) molecules from the first catalytic conversion bind to CO molecules to form CO2.  From a hydrocarbon compound, hydrogen and carbon molecules split and combine with oxygen to form CO2 and H2O.

If your car catalytic converter is damaged or not working correctly, you will not pass the emission test.

After the whole process, no longer harmful exhaust gas reaches the end of the pipe, where it is released into the atmosphere.

The catalytic converter must be in the best condition for your vehicle to pass the emission test.

What could be wrong with your catalytic converter?

Damaged catalytic converters can not only cause your vehicle to pass an emission test but can also damage adjacent parts, resulting in more expensive repairs.

Car Catalytic Converter

Reasons for premature failure of catalytic converters include:

  • Contamination from substances such as antifreeze and oil
  • Depths that damage catalysts
  • Problems with engine performance

Foreign matters such as coolant and oil can leak into the exhaust due to the engine’s high flow problems.  Such contaminants can quickly destroy your car catalytic converter. Besides this, problems with engine performance can also damage your catalytic converter.  If you want to purchase automobiles parts, visit The Auto Parts Shop today and save your money from costly repairs.