Skip the auto shop - Our mechanics make house calls

Q: When A/C unit is off, vents still have air flow

asked by on

While driving my car, I have noticed that when the A/C is off, the vents still have some air flowing from them. Also, while the A/C is “Off” and I turn the temperature knob to Cold, then the air comes out cold (but the A/C unit is “Off”). Just for your info, this also happens with the heater - but it is summer here right now.

When I’m in a stopped position, it doesn’t do it. It only happens while driving and I especially notice it when I’m on the interstate. I called the dealership and they said this is normal for the purposes of ventilation. Do you agree with them and is there any way to prevent the constant air flow?

A: This type of ventilation is typical on most...

This type of ventilation is typical on most cars. Try setting the controls to "Recirculate" mode and see if that helps. The Recirculation setting typically closes off the flow of outside air from entering the passenger compartment. At highway speeds, there usually is enough ram air flow, even with the fan off, to feel some airflow into the passenger compartment. It is also possible that you may be experiencing a GM strategy to always have some fresh airflow into the cabin.

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・Save up to 30%

Get a quote

What others are asking

Q: White smoke coming from exhaust.

White smoke is an indication of coolant burning, especially if you having to add coolant frequently. If the white smoke is coming out the exhaust pipe then it is most likely being consumed in the combustion chamber. A common cause...

Q: I've been noticing that my 2012 Chevrolet Sonic rumbles when going over bumps. I have about 60k miles on it, could it be the sway bar?

Hi there. If the sway bar was at fault, the noise would also be present when turning and a possibility of excessive body roll when turning. The source of noise over bumps can be difficult to diagnose since the bumps...

Q: Truck cranks but won't start - 1997 Chevy C1500

It sounds like you may have an intermittent electrical problem. I would recommend having all of the wiring that is in your fuel system checked to ensure that it is all in good condition. If any wiring has any damage...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...