No, a blower motor relay and a blower motor resistor are distinct electrical components, though they work together to control your vehicle's heating and air conditioning (HVAC) fan speeds.
A bad blower motor relay acts as a faulty switch, preventing electrical current from reaching the fan. Common symptoms include a blower fan that does not turn on at all, a fan that stays running even when the vehicle is off, weak or inconsistent airflow, or clicking sounds from the dashboard.
Diagnosing a faulty blower motor versus a bad resistor typically comes down to what fan speeds are working. If the fan only works on the highest setting, the resistor is usually the culprit. If the fan doesn't work on any speed, or if it makes strange noises, the motor itself is likely failing.
The average cost for a Blower Motor Relay Replacement is between $109 and $133. Labor costs are estimated between $50 and $73 while parts are priced between $59 and $60. This range does not include taxes and fees, and does not factor in your unique location.
The blower motor resistor can be removed after the bolts have been removed. The wire should be linked to the blower motor's positive terminal, and the negative terminal should be attached to the blower motor's negative terminal. This will turn off the resistor and allow the blower motor to run at full speed.
If the blower motor is operated with the resistor assembly removed from its location, it will likely cause the blower motor resistor to fail. Excessive blower motor amperage due to a faulty blower motor or restricted cabin air filter should also be considered or possibly replaced to prevent repeat failures.
Nearly all of the relays on a car, including the blower motor relay are built to last for as long as the car does.
Common indicators that a relay is malfunctioning include unusual clicking noises, failure to activate, and intermittent operation. These symptoms can signal underlying electrical relay problems that require attention.
To test a blower motor resistor, set your multimeter to measure resistance (Ohms). Disconnect the resistor and measure the resistance between the common input pin and each speed pin. If you read "OL" (Open Line) or zero resistance, the resistor or its thermal fuse is blown and needs to be replaced.
Which one to replace? If high setting works and medium and low do not, replace the resistor. If blower motor is spinning but makes noise, replace the blower motor. If you hear noise and only high setting works, replace both.
When a resistor goes bad, its internal resistance changes. It will generally either fail open (stop the flow of electricity entirely) or drift in value (block too much or too little current). This can cause the circuit to malfunction, overheat, or fail completely.
To determine if a relay is blown, you can perform a simple swap, a click test using a battery, or a thorough diagnostic with a multimeter. A blown relay usually causes a component to stop working entirely or operate intermittently.
The blower motor relay is typically located in the main engine bay fuse box (Power Distribution Box) or a secondary fuse panel under the dashboard on the passenger side. It is usually a small black, grey, or green plastic cube, often labeled "BLWR," "HVAC," or by a fan symbol on the fuse box cover diagram.
Resetting a blower motor typically involves cycling the power, checking for tripped thermal switches, or adjusting your thermostat. These methods apply to residential HVAC systems, though the exact steps vary depending on whether you are working on a furnace, an AC unit, or a car's blower motor.
If the blower motor relay becomes faulty or fails, it can result in issues such as the blower motor not starting, insufficient airflow, or irregular motor speed. In such cases, it may be necessary to replace the blower motor relay to restore proper function to the HVAC system.
Most blower motor relays cost around 15$ to $60.
Testing a blower motor relay involves a quick "swap test," an audible click test using a 12V battery, and a continuity check using a multimeter. This helps determine if your HVAC issues stem from a faulty relay, a blown fuse, or the blower motor itself.
(1) Put the clip to the starting point of your strip(i.e. on the most lefthand side). (3) Next to this clip, put another clip,leaving a space of around 1/2 to 1 cm. (4) Connect your multimeter probes to the clip and check the resistnance. (5) Adjust the position of the second clip to get the desired resistance.
Replacing a blower motor resistor typically costs between $90 and $300 for parts and labor. The part alone runs about $20 to $100, while labor takes a mechanic 30 to 90 minutes, adding another $50 to $200 depending on your vehicle's make and model.
Introducing the Blower Motor Resistor Bypass Kit, the ultimate solution to fixing a faulty blower motor resistor in your vehicle. This innovative product allows you to bypass the resistor entirely, providing a direct connection to the blower motor for maximum efficiency and power.
A blower motor resistor typically burns out due to a failing blower motor drawing excessive electrical current, restricted airflow from a clogged cabin filter, or internal thermal and moisture damage. Over time, these factors cause extreme heat that melts or fries the resistor's sensitive internal components.
To test a blower motor with a multimeter, first disconnect the motor from its power source. Set your multimeter to the Ohms (Ωcap omegaΩ) or continuity setting. Check the internal windings by touching the probes to the motor's power terminals. A healthy motor will show a low resistance reading (usually between 555 and 505050 Ωcap omegaΩ).