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Most car manufacturers use a series of resistors to make the heater blower motor run at different speeds. And when one or more of these resistors burn out, you’re usually left with only one heater blower motor speed—high. The resistor module is easy and inexpensive to replace.
Why does my car blower only work on high?
When a resistor fails, the fan will often run only at higher speeds or the highest speed, no matter what fan speed is selected. If little air is coming through the vents (hot or cold), then it could be because the blower motor for the fan or a switch or resistor that controls fan speed isn’t working.
Why does my fan speed only work on high?
When a blower resistor fails, the highest fan speed usually is the only one that still works because it essentially bypasses the resistor and receives the maximum amount of voltage. When the resistor is working, it reduces the amount of voltage going to the lower fan speeds, so the fan runs slower.
How much does it cost to replace a blower motor resistor?
The average cost to replace the blower motor resistor at a repair shop is between $44 and $55 in parts and $70 in labor costs, for a total cost of around $114 to $125.
Why will my heat only work on high?
If your heater only blows when the setting is on high, this may suggest that you have a faulty blower motor resistor. The highest speed setting may still work because in most cars in the highest fan speed settings the current bypasses the blower motor resistor.
Why does my blower motor resistor keeps melting?
Trent, one of the biggest reasons for blower motor resistors to have shorten life is actually because of faulty blower motor drawing too many amps, some times melting wires/plugs, heating up resistors shortening their life. Many Dodge forums tell of this problem.
How do I know if I need a blower motor or a resistor?
Typically, if the fan will work on some speeds but not on others, the resistor is suspect. Okay, let’s say there’s no melting going on, but your fan doesn’t work on all speeds. Typically, if the fan will work on some speeds but not on others, the resistor is suspect.
What is blower resistor?
The blower motor resistor is responsible for controlling the blower motor speed. The change in resistance controls the current through the blower motor, which in turn limits the speed that the blower motor spins at.
Where is the blower resistor located?
It’s located inside the dash, often on the opposite side of the steering wheel or inside the engine compartment on the firewall. A blower motor resistor or a blower motor control module is the part that controls the speed of the blower motor.
How do you test a blower motor resistor?
Place one lead of the Ohmmeter on terminal 1 of the resistor. Place the other lead on terminal 2 and check against specifications. If this circuit is open, showing infinity on the Ohmmeter, the blower resistor must be replaced. Move the lead from terminal 2 to terminal 3 and check this reading against specifications.
How much does a new blower motor cost?
Replacing a blower motor costs $450 on average with a typical range of $250 to $800. With a warranty, you might pay as little as $150 for labor alone. For high-end models, like those with large motors or access issues, you might pay as much as $2,000.
Does the blower motor resistor control heat?
The blower motor resistor is an electrical component that is a part of the vehicle’s heating and air conditioning system. It is responsible for controlling the blower motor’s fan speed. A failed blower motor resistor can cause issues with the operation of the entire heating and air conditioning system.
Why does my heat only work when Im moving?
Air gets into the system when the coolant is low for one reason or another. Having your heater only work when the car is moving is a big indicator of this issue. You can purchase a coolant system test kit that will tell you if there is air in the system. A common cause for this issue is simply a bad radiator cap.
When my car is idling the heater blows cold air?
You may have trapped air in the cooling system or the heater core may be partially plugged up. Engine coolant is delivered to the heater core through two heater hoses.
Why does my heat stop working when I stop?
Why does the car heater blow cold air when I’m not driving? This problem is usually in cars that have an idling stop feature. If the engine is turned off for a long time when you are stuck in the traffic, this can lead to poor circulation of hot engine coolant in the heater core leading to poor heating.
How do I know if my blower motor relay is bad?
If you have a faulty blower motor, you may experience low airflow from the vents, even when the fan is on high. There will be no air coming from the vents if your fan isn’t working due to a bad blower motor resistor. Blown relay circuit fuses or melted relays are more serious signs of a bad blower motor relay.
What would cause a resistor to burn up?
Burning of Resistor When a resistor has been overloaded with voltage exceeding its power rating, the resistor will become very hot to touch, darken considerably and possibly even melt or catch on fire. Although a resistor may appear damaged at this point, it can still be functioning.
What is blower motor relay?
In a blower motor, the relay supplies the power that allows the fans to circulate warmed air. Essentially an on/off switch, the blower motor relay’s reactions start and end the heating process in HVAC systems by controlling the flow of current between the power source and the motor.
How do you know if a resistor is bad?
A good resistor should test within its rated range. A bad resistor will either show infinite resistance or a measurement far higher than its rated resistance. In either case the resistor is no longer functioning properly.
