Skip the auto shop - Our mechanics make house calls

Q: Heater only works on high. Heat is not hot.

asked by on

Car takes awhile for the heater to blow hot air. It only works on high. The air is not that hot.
My car has an automatic transmission.

A: If your heater only blows when the setting ...

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. In some cars, if the resistor is failed, the fan may stop working completely. Another reason a blower motor resistor may fail is when the blower motor has a mechanical problem or when a foreign object jams the blower motor fan blade and prevents it from spinning freely. This leads to increased current through the resistor and causes it to overheat and fail.

The lack of heat being generated by your system may indicate a faulty heater core. The [heater core]((https://www.yourmechanic.com/services/heater-is-not-working-inspection) is a small radiator like unit that circulates the hot coolant from the engine through the heater core which then uses this warm coolant to heat the inside of the car with the help of the blower motor that blows the warm air through the vents inside the car. I would suggest having an expert from YourMechanic come to your location to diagnose your heating system.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: My car won't start

It could be something as simple as a dead battery. The battery may have enough power to light things on like the radio, but not enough power to start the car. Try jump starting it or you can call Hyundai...

Q: Car does not go into gear.

Most of the time when this issue occurs it is due to the shift interlock solenoid going bad. Systems that use this part usually have a manual override button near the shifter in order to manually shift into a gear....

Q: My car started cutting out after driving for a little while?

Hi, thanks for writing in. If the car had been sitting for 9 months, there may be a good chance of it having something as simple as bad fuel or bad spark plugs. I would recommend starting with a basic...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.