My 2005 Chevy Silverado with dual zone climate is occasionally blowing hot air on the driver's side and cool on the passenger. It usually works fine for a few minutes before it begins blowing hot air. Once it starts blowing heat, it seems to continue until I park for a while. It doesn't always have this problem. I'm guessing it's a vacuum or electric problem. I assume that low refrigerant would cause both sides be hot.I'll probably be taking it to a dealership, but I'd like to know more about the problem before I do that. This is a common issue. Sometimes the door actuator needs to be reset, as it gets confused. When I had this problem in my Avalanche, I found that turning the temperature all the way to the 90 degree max setting (when set to equal cooling for both sides), waiting a few seconds for the door to stop moving, and then turning the temp back down, would resolve the issue temporarily. When I took it to the dealer, they said they couldn't find anything wrong with it.

After getting tired of dealing with the issue, I tried searching profusely on-line, and eventually found this page which describes the issue, and a reset procedure to try, which involves removing the fuse. I found this to completely solve the problem for me. On a dual AC 2010 Ford Edge with both thermostats set for AC, the passenger side blew hot air, the driver side cold. I thought at first it may be a faulty blend door actuator on the passenger side. I changed a very dirty cabin filter and started the engine.....immediate cold air blew on the passenger side! Not sure if a dirty cabin filter can confuse the actuator sensor but my system now works perfectly.Browse other questions tagged chevrolet ac silverado or ask your own question.It’s that time of year again.  The days are getting hotter.  If your car's air conditioning system is blowing hot air, don’t wait until the next heat wave comes.  Take care of it now. What Can Go Wrong?Car air conditioning systems are complex, and there are many things that can cause the system to fail.  

In the illustration below, you can see the some of the parts that make up an automobile's air conditioning system. The system includes the control system, sensors, switches and vacuum lines as well as the refrigerant system. A problem with any of these components can cause your car's air conditioning system to become weak or stop working. These components are tucked under the dash panel and connected through high and low pressure lines to the engine compartment, the condenser, the compressor, and the drier. Our Process for A/C RepairsWhen you come in to get your air conditioning system fixed, the first thing we need to do is diagnose the problem.  We give you an information sheet that includes the items covered in this blog post to help explain the process.  If you like, we can even show you the sheet our technicians use in checking and repairing an air conditioning system. Diagnosis can take from one to two hours, depending on the complexity of the problem. Here are some of the checks that we perform as part of the diagnosis

Once all these checks have been completed, we can provide you with a report of any leaks as well as an estimate of the cost to repair the system. Leaks in the A/C SystemSometimes air conditioning leaks can be very hard to find because we are looking for an invisible gas. best window ac unitsThe dye (mentioned in item #6) helps us to locate the leak. estimated cost to replace ac unitOcassionally the leaks are so tiny we have to let the customer drive the car for a few days then have them come back to recheck for leaks.window ac unit no window Leaks in the engine compartment are easier to find, but leaks from the evaporator are much more difficult because the evaporator is tucked away behind the dash panel.  In the photos below, we are working on the evaporator core.  

As you can see, the dash panel has to be removed to repair the system. If the air conditioning system has failed because of an electrical or electronic failure then we handle it in the same manner as other types of automotive electrical or electronic issues.  This involves performing various tests to pinpoint and then correct the problem. A common failing of auto air conditioning systems can be leaks from the service caps that are used to connect the gauges. This is one of the areas that we check for leaks. If you don't currently have a quick seal service valve cap, a good preventive maintenance measure is to install one.  It can help to protect against these types of leaks. So...be sure you're ready for the next heat wave.  We even have a diagnostic form that you can complete and bring in to your service visit. It can help speed the diagnosis process.Written Written Ideally you need warm, dry air. Warm air can hold more moisture and encourages evaporation, and dry air is carrying less to start with.

The moisture from the glass is absorbed by the air directed at the windows.Warm air is easy, but somewhat counter-intuitively, you can use the car’s air conditioning if equipped. This cools the air, which reduces the amount of moisture the air can hold. This excess moisture condenses out, so drying the air. The heater then warms the air back up, giving you warm, dry air that’s more effective than the heater alone.Written First of all the air must be dry. Otherwise you will add more fog.Hot dry air is better because it will hold and therefore absorb more moisture from the damp windows.Cold dry air is better than cold damp air, but not as good as warm dry air.In usually cold damp day the best source of dry air is to run the air conditioner even if its near freezing, This will condense out any moisture in the conditioned air and therefore blow dry air albeit cold across the windshield removing the internal moisture by condensation. Otherwise there is no assured source of dry air. Most cars with airconditioning when you set front window defrost will turn on the airconditioning and blow that air over the window.