Silverado blows heat out of drivers side, and kind of cool out of passengers

ID Status Date Year Make Model Transmission Type A/C Controls Public/Private
#16384 Closed 2009 Chevy Silverado public

I have a 2009 silverado 1500 LTZ with the 6.2 in it. The drivers side blows heat, and the passengers blows almost cool. All of my blend door actuators operate correctly, and my doors open and close as they should, my freon level is in range, and my high pressure and low pressure read as they should. When I say drivers side blow hot, I mean as hot as you can imagine air possibly blowing.


Well, either the driver’s temperature door actuator is not working correctly or the door it attaches to is broken inside the box. The actuator is located under the passenger side of the dash just above the transmission hump in the floor pan.

There is a notch on the actuator shaft and it should rotate between the two hash marks on the actuator case. You may need a mirror to see the rotation from full hot to full cold. If it seems to work okay, I would remove the actuator and turn the door shaft by hand. You should feel a solid thunk when it bottoms out in either direction. Also you should be able to change the temperature if the air coming out of the driver’s side vents.

I already did that, new actuator, pulled it off again today to try turning it, it rotates like it should, and can hear the audible thunk when the door closes/opens even when I manually operate it I cannot get cold out of drivers side.


Okay, when you manually turn the door shaft can you at least get rid of the heat condition even though the air never turns cold?  Meaning will the temperature on the driver’s side come down to slightly warmer than the ambient air temperature. Full heat should be around 150+ degrees F.  Full cold should be between the actual outside temperature and possibly 10 degrees warmer.  If so, you likely have a problem on the refrigerant side of the system. To assist with that type of issue, I need to know a few things from you.

What are the temperature and humidity conditions where you are at?

What are the static and operating system pressures? Both sides, High and Low pressures.

When was the last time the refrigerant system was serviced, if ever?

When was the last time the system operated as designed?

When and how did the system fail? How long ago? Was it gradual or sudden?


It is the consistent when turning the door by hand, full heat, never colder, my high pressure is between 200-250, and my low pressure right at about 28, yesterday when I was messing with it was 95F outside with about 85% humidity. The AC was serviced when I bought it about 7 months ago, it worked beautifully. Suddenly in the middle of driving it straight heat on drivers side 2 months ago, which led to me belive it was my door actuator. It is not my daily driver, I am at a loss what it could be at this point

On another note, this led me to belive it was my ambient air cab temperature sensor, but the reading a pulled off of that was spot on.


The temperature not changing with the manual door movement would suggest that a significant portion of the door may be broken and allowing heat to come through. Or there is an internal obstruction that is preventing full closing of the door.  I am not there is person to observe so I would suggest you check that again after letting the truck sit overnight. Make a base line test before starting the engine and rotate it several times as the engine warms up and reaches full operating temperature. You may want to use a digital thermometer in the dash vents to monitor the actual temperatures.

Another suggestion on the refringent side is to check the temperature of the high and low side lines near the passenger side of the underhood firewall. There is an orifice tube inside the high side line assembly just after the union nuts. The input side should be warm to hot and should turn very cold just after the orifice tube. The low side line in that same area should be equally as cold as the cold portion of the high side line after the orifice tube. Also with your humidity, both should be sweating or wet with condensation. They may not be equally as cold when the system is first started but should be within 5 to 10 minutes of operation.

Just checked them, my pressures are good, and my door is rotating all the way, opening and closing like they should, the only thing I can think of is something is wrong in my head unit for my HVAC controls


You are missing something in your testing and observations or there is an internal door problem with the HVAC case.

Here are a few things to consider.

If the refrigerant portion of the system is operating correctly (both lines cold/35ish degrees and sweating) and there is merely a controls issue with the temperature door, then manually moving the door will produce cold air out of the vents. If you could keep the compressor on and the blower motor working, you could literally throw the control panel and actuator away and still get cold air out of the vents. The only way around this scenario to have heat coming out of the vents is an internal bypass of air around the closed temperature control door, ie a damaged or obstructed door.

Now assuming there are no internal door problems and you manually move the door to the full cold position, the only way you will not have cold air blowing out is that there is no cold air source, ie there is a refrigerant system fault.  I cannot stress enough that proper refrigerant charge is critical. The system can have “good” pressure readings but be slightly under or over charged. Either condition can result in a poor to no cooling effect. Also gauges can be inaccurate. That is why I always back up gauge readings with feeling the lines.  Another little know fact about modern a/c systems is that refrigerant charge levels can manifest in a condition where there is cooling on one side of the dash but not the other.  Has to do with btu exchange, thermal absorption and split air flow through the evaporator core. Which side is affected is determined by which side of the vehicle the refrigerant flow comes from. In some vehicles there could be as little as a one ounce variance that will result in poor cooling. In the case of your truck, 6 to 8 ounces of under charge or anything more than 4 ounces of overcharge will cause an issue. The pressures may seem within range especially on your truck since the high side service port is after the condenser.

There could also be an internal blockage of the condenser or the orifice tube. The orifice tube is of a variable design so it could have also failed even though the pressures seem okay. More reasons to feel what is actually going on in the system.

Lastly can you confirm the location of the actuator and door you are working with is in the same location as the one in the linked article below?

2009 Chevrolet Silverado Driver’s Side Air Stuck On Heat

I have just cut a little access hole in front of the door (yes I will seal it back up, I can watch the door operating properly, when it is closed, no only cold air coming out of acess hole, and when it is open, only hot air coming out of the acess hole, and yes, it is under the passengers side kick panel. Also, both of my lines, low and high pressure, are ice cold and sweating right past the drier, the AC clutch is spinning like it should, and I tested both my pressure sensors and everything checks out. I’m at a complete loss what would be causing this.


Can I assume you cut an access hole in the front of the case and not the door?

Can you clarify this statement? “ when it is closed, no only cold air coming out of acess hole, 



I have sent breakdown of the case in two separate attachments.

Yes, I cut a hole in the case not the door, I would upload a picture but for some reason it won’t let me, and I’m referring to the temprature of the air coming out of the hole in the case that I cut.

Sorry I just read my statement you replied with, that was a typo. When it is closed, only cold air is coming out of the hole.


Well it is good to hear that there is cold air somewhere in the system. At this point I can only think of two things.

Number one is that something is broken, out of place or missing inside the air distribution box.

Number two and it would be a long shot, it could be possible for the evaporator core to be dirty enough that air cannot properly flow through it for adequate btu transfer. If the surface of the evaporator core is dirty/restricted enough some air could flow through it without being properly cooled. You would need to remove the blower speed controller and possibly the blower motor to inspect the fins of the evaporator core. Unless your truck happens to have a cabin air filter. If so you can remove the filter to inspect.

The way that the air flows through the case is the blower motor forces all air through the evaporator core where it is cooled and dried (with the compressor on). The air then approaches the temperature doors. If the doors are in the full cold position the air bypasses the heater core and comes out of the vents as cold air. As the temperature doors are moved towards the warm/hot positions some of the air is forced through the heater core where it is warmed back up. In the full heat position all of the air is forced through the heater core before exiting through the selected vents.

I was thinking the same thing, but, it went out so sudden that it was like a switch was flipped and then heat just comes out of the drivers side, my wife made a good point a little bit ago, it was right after I jumped her car that it happened, so I don’t know if that coralates at all with the issue, or if you’ve ever heard of something like that.


I have seen voltage spikes cause the actuators to move to the default full heat position. The problem generally corrects itself in the next ignition cycle or if you were to perform a system recalibration. If the actuator is moving in the full 90 ish degree arc from full hot to full cold that would not be  concern.

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