What happens when the resistor on a blower motor fails?
The coil resistance causes them to heat up, thereby reducing the amount of voltage that can flow to the blower motor. When a resistor coil burns out, you lose that fan speed. A blower motor resistor can fail in several ways; since many are designed in series, if one resistor fails, you loose speeds 1-3.
What to do if your blower motor only works on high speed?
If your blower only operates on its highest speed, chances are you have the series type of blower motor resistor. This is the most common failure mode. To repair the problem, simply replace the resistor block. It’s usually located in the ductwork (to keep the coils cool) below the glove box.
How does a 3 speed blower motor work?
Older style blower motor resistor with exposed resistor elements. The blower motor resistor is what’s responsible for giving you three blower speeds. The resistor block contains three different high resistance coils. Think of these coils like a filament in a light bulb.
Why does my Ricks free auto blower motor not work?
A clogged cabin air filter reduces airflow through the ducts, increases current draw on the blower motor and can cause blower motor resistor overheating and premature failure. If you replace the resistor and it burns out again, check the current draw on the blower motor.
What are the symptoms of a failed blower motor resistor?
Blower motor resistor problems. Problems with a blower motor resistor are common in many cars. The most common symptom of a failed blower motor resistor is when the heater fan only runs at high speed and doesn’t work at low speeds.
What happens if the blower motor only works on high speed?
In other designs, the failure of 1 resistor means you lose only one speed. However, most car makers bypass the blower motor resistor completely when you move the fan speed switch to high. If your blower only operates on its highest speed, chances are you have the series type of blower motor resistor. This is the most common failure mode.
Where do I replace the resistor on my blower motor?
To repair the problem, simply replace the resistor block. It’s usually located in the ductwork (to keep the coils cool) below the glove box. Unplug the electrical connector, remove the screws and replace the unit. Replacement blower motor resistor blocks are usually available from any auto parts store or the dealer.
A clogged cabin air filter reduces airflow through the ducts, increases current draw on the blower motor and can cause blower motor resistor overheating and premature failure. If you replace the resistor and it burns out again, check the current draw on the blower motor.
How does a high speed blower motor work?
The blower motor resistor is what’s responsible for giving you three blower speeds. The resistor block contains three different high resistance coils. Think of these coils like a filament in a light bulb. The coil resistance causes them to heat up, thereby reducing the amount of voltage that can flow to the blower motor.