Skip the auto shop - Our mechanics make house calls

Q: Heater

asked by on

The.heater only runs on cold an the person who had it last said that there some type of switch under the dash but I'm not sure where it is
My car has an automatic transmission.

A: The heater uses hot engine coolant to warm ...

The heater uses hot engine coolant to warm the vehicle cabin. If the heater is blowing cold, the first thing to check is the coolant level. Low coolant, or a problem somewhere in the cooling system, will affect heater operation. Other potential causes include a thermostat that is stuck open (not allowing the engine to reach operating temperature), air in the cooling system or a bad heater core. I recommend having a professional, such as one from YourMechanic, diagnose and repair this heating problem for you.

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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Air conditioner & heater problem

The problem you are describing is possibly caused by mis-operation of the "flapper doors" that control and direct air flow throughout the various HVAC outlets. These doors are operated by cable or by servos. It is also possible that there...

Q: Front right blinker not working

Based on the lack of history, you most likely have a bad bulb or a corroded electrical socket connected to the bulb. A visual inspection of the contacts within the socket will determine the issue. In some rare cases, the...

Q: Car starts then immediately stalls out.

Hi there. Check the engine oil level and make sure that it's full. Top off the oil if it's low and recheck to see if the engine is still stalling. The symptoms that you describe are as if the engine...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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.