My blower switch only works on #2 speed & high speed could this be the blower resistor?
I hav replaced the 4 speed blower switch on the dash. MY A/C does work
My car has 150000 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hello there, a few common faults can cause your 1972 Oldsmobile Cutlass to only work on the #2 speed air flow. You are correct, the blower motor resistor could cause this fault. Other likely causes would be the fan control switch, blower motor, or a wiring harness fault. A qualified technician, such as one from YourMechanic, will be able to diagnose your air flow issues and move forward with any repairs required.
How to Identify and Fix Common car Problems ?
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Odds are good that the fan switch may be at fault, but a more likely reason is that a blower motor resistor that controls the voltage going to the blower has packed it in, resulting in only one speed remaining operable — usually the highest speed, which you may not always need depending on the temp of the outside air.
When a resistor fails, the fan will often run only at higher speeds or the highest speed, no matter what fan speed is selected. In some vehicles, though, the fan may not work at all, and only a little may come through the vents.
Blower resistors are resistors which are used to control the fan speed of automotive blowers. The fan speed can be changed either by switching the blower resistor resistance mechanically using a rotating lever, or electronically by the air conditioning system.
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.
When increasing the blower speed, loosen the setscrew a little bit. This is the part that holds the pulley to the furnace`s driveshaft. Turn the pulley one rotation clockwise on the shaft. If you want even more speed, do two rotations.
Poor Capacitor
More than 90% of ceiling fans problems happen because of a bad capacitor. Once the capacitor stops working, power cannot be transformed to the motor. Further, this can cause your ceiling fan to run slower than the usual speed. You can replace a faulty capacitor by replacing some of its inner components.
If the resistor shorts or fails, it may cause the blower motor to remain stuck on one fan speed. The heating and air conditioning systems may still function at one speed, however the resistor will have to be replaced in order for full functionality to be restored.
The blower motor switch is the actual switch or button on the dash that you use to increase or decrease the fan speed. The blower motor IS the fan. The blower motor resistor is what allows the fan to work at different speeds as opposed to just off and on.
On most modern cars, the cooling fan is controlled by the Engine Control Unit (ECU) which gets a signal from the coolant temperature sensor. If it`s not working, the fan won`t turn on when it needs to, which means the engine might overheat.
The blower motor resistor is responsible for controlling the blower motor speed. In the past, this was done by varying the voltage supplied to the blower motor. In newer applications, the blower motor resistor is actually a solid state module that sends a varied signal to the blower motor.
An increase in blower speed can sometimes improve the flow of warm air through your home. A decrease can make the system quieter. You can increase or decrease the blower speed by slightly adjusting the pulley on the blower drive motor.
Depending on its intended use, a cordless leaf blower with a CFM between 400-700 should be powerful enough to greatly ease your fall yard chores. If you have a small yard with little debris, choose one with 200-400 CFM.
Your typical CPU fan speed ranges from about 600 RPM to 3000 RPM. However, for a clearer picture, check your CPU Cooler`s Product Page. The ideal CPU FAN Speed is a middle ground between: Higher Speed / RPM = cooler CPU = higher CPU performance, and.
The speed of Fan can be slow down by simply by connecting a bulb or any other resistive load in series between the power supply and fan. In this method if the watt of connecting Load is increased then the speed of Fan is also increased.
If the fan runs faster, your AC system will cool your home much more quickly. The issue with this is that the system won`t be able to absorb that much moisture from inside the home when it runs for a shorter time. Reducing the fan speed also reduces the rate of cooling.
The blower motor resistor is responsible for controlling the blower motor speed. In the past, this was done by varying the voltage supplied to the blower motor. In newer applications, the blower motor resistor is actually a solid state module that sends a varied signal to the blower motor.
Problems include dirty filters, broken wires, poor voltage supply and faulty limit switch or capacitor. You can test your limit switch with a multimeter, and clean the blower motor`s wire coils. If this doesn`t work, you may need to replace your furnace blower motor.
The blower motor relay is the electrical switch that is used to supply the power for the vehicle`s blower motor. The blower motor is the component responsible for pushing air through the vents of your vehicle`s heating and air conditioning systems.
Problems include dirty filters, broken wires, poor voltage supply and faulty limit switch or capacitor. You can test your limit switch with a multimeter, and clean the blower motor`s wire coils. If this doesn`t work, you may need to replace your furnace blower motor.
The most likely cause of fan speed control failure is a resistor failure at the fan`s motor, although it can also be a defective control switch or burned-out fan motor.
The most likely cause of fan speed control failure is a resistor failure at the fan`s motor, although it can also be a defective control switch or burned-out fan motor.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
My blower switch only works on #2 speed & high speed could this be the blower resistor?
ANSWER : Hello there, a few common faults can cause your 1972 Oldsmobile Cutlass to only work on the #2 speed air flow. You are correct, the blower motor resistor could cause this fault. Other likely causes would be the fan control switch, blower motor, or a wiring harness fault. A qualified technician, such as one from YourMechanic, will be able to diagnose your air flow issues and move forward with any repairs required.
Ac compressor clutch isn’t engaging on high fan speed setting while it engages on the prior three fan speeds which are all slow.
ANSWER : The blower not working is most likely due to a fault with the blower resistor. When you go to high blower speeds the A/C may disengage the compressor if the cycling switch cycles or the high pressure switch gets over pressurized, shutting the compressor off. The first thing to do is to get the blower working correctly then test the A/C pressures using A/C gauges. If you’d like to get this fixed, consider YourMechanic, as a certified technician can diagnose your A/C issue and fix it accordingly. Good luck.
How do I know if it’s my blower motor resistor or the resistor switch that’s not working?
ANSWER : The referenced parts are tested with an ohmmeter. The resistor block must have a specified resistance across each element on the block. However, if any resistors are open (infinite resistance), the block is just condemned and replaced automatically. Occasionally, you might be able to see that the resistor block is obviously broken (elements are open). Switches are tested using an ohmmeter or continuity tester. There are other electrical components, and wiring, in the system that can cause it not to work. If you desire that this problem be diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a blower motor diagnostic and the responding mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic.
Fan only works on highest speed. 2008 Volkswagen Passat
ANSWER : Hi there, thanks for writing in about your 2008 Volkswagen Passat. If the blower motor resistor and connector are good, then the only other thing that can cause the problem is the blower control switch or connector. Check the resistor to make sure you have good connections and that the resistor is not blown again. If you need help having this checked, a qualified professional from YourMechanic can come to your car’s location to inspect the cooling system and have this corrected.
Front A/C blower motor working incorrectly.
ANSWER : One sure way to rule out the blower motor itself would be to observe voltage while the issue is happening. If the voltage being fed to the blower motor fluctuates, the problem is on the control side of the circuit and possibly the resistor. Hire one of our mobile experts to swing by and test the electrical system and track down this bug.
Blower Motor only working on highest speed.
ANSWER : You mentioned that you started to smell something. This may be a sign that the blower controller or the resistor was burnt out when it was hooked up wrong. You should try replacing the blower controlling resistor that you hooked up wrong. But like you mentioned, it could also be a fuse problem that has shorted. If you would like to have this looked at, have a certified technician, like one from YourMechanic inspect the wiring and determine what should be done.
Replaced blower motor resistor on a 06 honda accord 4.2l. Only blows on high regardless of what speed I set it on
ANSWER : Hi there. Assuming the original problem was no blower motor speeds at all, leads me to believe that the replacement blower resistor may be your issue. High blower motor relay stuck closed would of given you high speed only, prior to the blower resistor replacement. A circuit test should be performed to prove a faulty blower switch. To keep from replacing unnecessary parts, I recommend having your vehicle’s A/C issue inspected and diagnosed by a certified technician from YourMechanic.
My dash board don’t work my front light work when I change my light into high beam and my back window won’t go down
ANSWER : As unfortunate as it is, your vehicle would be considered flood damaged. Diagnosing electrical problems in a flood damaged vehicle is nearly impossible. This would take many hours or even days to determine which wiring harnesses and circuits have been affected. Then nearly all of the wiring under the dash would likely require replacement as well as many sensors and switches. On a BMW vehicle, the amount of wires and switches are likely more than that of a lower end vehicle. Due to the inefficiency in cost, you would likely be able to purchase another BMW like yours for less than what it would cost to fix your car. Many insurance companies would consider this type of damage to total out the vehicle unfortuantely.
