Why Does My Heater Only Work On High?

Published date:

2022-10-12
Score: 4.69/5 (37 votes)

Are you searching for an answer to the question: Why does my heater only work on high? On this page, we've collected the most accurate and complete information to ensure that you have all of the answers you need. So keep reading!

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.

You may wonder, why does my blower 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.

Similarly one may ask, how much does it cost to fix a blower motor resistor? between $50 to$150How much does a blower motor resistor cost? To replace the blower motor resistor, it would cost you anywhere between $50 to$150 – this includes the cost of equipment and labor. However, by doing it yourself at home, you can save up to $70.

Besides above, how do i know if i need to replace the blower motor or the resistor? Here are some common signs that your vehicle's blower motor resistor is bad:

  • Loss of HVAC fan control (total or certain speeds)
  • The fan only works on its highest speed setting.
  • No air coming from vents.
  • Intermittent or inconsistent fan speed.
  • Likewise, why does my heater only work when i rev the engine? However, if the heater only warms up when you rev the engine, that is a sign a component is amiss. One of which is the heater core. Although the thermostat greatly affects the engine temperature, typically, the engine will overheat if it's deficient.


    How do I reset my blower motor?

    How to Find and Reset your Furnace Motor Blower

  • Step 1: Turn off the power to the furnace. ...
  • Step 2: Remove the blower compartment cover. ...
  • Step 3: Make sure the blower is completely cooled off. ...
  • Step 4: Locate the reset button. ...
  • Step 5: Press the button in (assuming that this is your issue and that the button has popped).
  • What are the signs of a blower motor going out?

    What Are Signs Your Blower Motor Needs to Be Replaced?

    • Poor or Airflow from Air Vents. This will be the first and most obvious sign your blower motor has a problem. ...
    • No Airflow At All From Vents. ...
    • Skyrocketing Energy Bills. ...
    • Strange Noises When You Turn on the Heat. ...
    • Overheating Blower / Weird Smells.

    Is there a fuse for blower resistor?

    A fuse is often located on the resistor board. The fuse only protects the low and medium blower speeds. High speed will still work if the resistor fuse is blown.

    Is it hard to replace blower resistor?

    How to Replace a Blower Motor Resistor. The blower motor resistor is usually extremely easy to access, but the hard part can be positioning your body inside the car to remove the part. The resistor is at the bottom of the HVAC housing or just behind the glove compartment.

    How do I know if my blower motor relay is bad?

    One of the first symptoms of a problem with the blower motor relay is a blower motor that does not function. As the relay is the switch that supplies current to the blower motor, if it fails internally, then power may be cut off from the blower motor circuit causing the motor to no longer function.

    How do I know if my heater resistor is bad?

    If you try to increase the air pressure and you feel no difference in the pressure blowing, then your blower motor resistor may be failing. A damaged blower motor resistor will work on one fan speed which may not be enough to keep the inside of your car cool or warm enough.

    What controls the blower speed?

    Blower resistorsBlower 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.

    What happens if blower speed is too high?

    If a blower speed is set too high, your AC might not be operating optimally. This is because the evaporator coil will not be able to adequately dehumidify the space in need of cooling.

    Is there a fuse for blower resistor?

    A fuse is often located on the resistor board. The fuse only protects the low and medium blower speeds. High speed will still work if the resistor fuse is blown.


    Why Does My Heater Only Work On High - What other sources say:

    Car Heater Repair Tips: Fixing a Blower Motor?

    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 ...

    Heater only works on highest setting - Car Talk Community?

    On low it runs through a resistor which may be fused. If you only have high, the low circuit or resistor is not getting current. Check fuses.

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    The blower motor resistor is prone to shorts, corrosion, and overheating. When the resistor fails, typically, the highest setting is the only ...

    Why does my air conditioner/heater fan only work on High?

    High speed bypasses the pack which is why it still works. The startup noise could very well indicate failing fan bearings--that could have ...

    Why Your Car Heater Only Works When Driving?

    Why Does My Car Only Blow Hot Air While Driving? ... Your car's heater works in tandem with your engine's cooling system. Many issues with inconsistent heat in ...

    Why Would My Heater Only Work On High? - Truckile?

    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 ...

    Blower Motor Only Works on High on Ford F-150 - RepairPal?

    The 2004-2014 Ford F-150 with manual temperature and fan controls may have problems with the the blower motor only blowing air on certain settings.


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