Q: AC blows hot and cold air at the same time

asked by on November 06, 2015

I live in a very warm area, so I notice right away whenever something is up with my AC. Half of the vents in my 2007 GMC Acadia were blowing warm air the other day. I find it pretty weird that only part of the AC broke. The truck has just under 70k miles on it and I haven’t really had major problems so far. What part should be inspected first?

If you are getting normal cold air out of driver’s side and warm air out of center and passenger vents then you most likely have a bad temperature blend door actuator for the passenger side on the A/C evaporator case. Your system has two of these actuators, one for each side of your dash vents. This controls the temperature by getting feedback from the inside ambient temperature sensor. The sensor looks at the drivers and passenger seat temperatures and can alter the left and right side of your dash temperature output to compensate. You could have YourMechanic scan and test your A/C system for problems. Once a thorough diagnostic report is produced and indeed the actuator is deemed to be the culprit, YourMechanic can provide you with the best estimate for repairing the failed part.

Was this answer helpful?
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・Fair and transparent pricing

Get a quote

What others are asking

What is the problem? No one can tell me

The vehicle idling in park with no A/C does not really require much need for the idle air control valve. Once the vehicle is put in drive, this will put a load on the engine as the A/C will require...

When I turn the ac on it makes a very loud squeal that stops after a few minutes. 2007 Jeep Commander

Hi there - It's possible that the tensioner/idler pulley for the serpentine belt(https://www.yourmechanic.com/services/loud-squealing-or-rattling-is-coming-from-engine-inspection) by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and...

Plugged heater core

Hey there. The heater core may burst if you use too much pressure to try and purge the core of blockage. The core gets blocked from using the wrong fluid in the vehicle. The coolant will get all brown and...

Related articles

Symptoms of a Bad or Failing AC Belt
If your car squeals when you turn on the AC, has cracks in the AC belt, or is unable to defrost the windshield, you may need to replace the AC belt.
The Best Used Cars to Buy If You’re Over Six Feet Tall
While While shorter than average drivers can have a tough time finding the right car, it’s equally hard for taller drivers, perhaps more so. If you’re feeling squished, or have to hunch over the wheel to drive, then you’re not...
What Causes the AC System to Leak?
Your car’s air conditioner is responsible for keeping the interior cool and comfortable on hot days. However, in order to do that,...