I have a 2004 Yukon with 160000 miles and about a year ago the AC would suddenly blow hot air just on the driver's side while the passenger side still blew cold. After a few weeks it then stating blowing hot air on both sides. The only way to correct it was to turn the car off and back on and then it would immediately start blowing cold again. Sometimes go 30-40mins with it blowing cold and then suddenly hot air and sometimes just 5-10mins. Recently I changed the pressure switch and and checked the pressure. The pressure was good. I am not sure if the pressure switch had anything to do woth this but immediatley after changing the switch, when the system would stop blowing cold air it was just the driver's side again and not both. Any insight would be greatly appreciated. Did you find out the exact issue? 05 Yukon XL does the exact same 42 out of 42 people think this isThe blend door actuator has some grease on the contactsSee how to do it here==> 187 out of 187 people think this is

You must relearn your actuator to blow hot or cold correctly. Turn on your A/C to the highest blower setting and let it run 5 minutes, then dial up the heat leaving the blower in highest position for five minutes. this should resent your actuator to correctly blow hot or cold. that's one way to fix it. I unplugged the old actuator planning to install my new one and decided to wait till the next day. I plugged the old actuator back in and drove to the store and it blew cold air all the way and has not blown hot for over two months now. I even got a refund for the new one I had bought. Remember, if you blowing cold or hot air the actuator is working..but it's out of sync..try these things before wasting your money on a new unneeded part. 33 out of 33 people think this is I relearned my actuator like David said and my AC works fine. in the truck for twenty minutes to test it out and it did not blow hot air. Will see if problem persists tomorrow. This happened on a 2005

Chevy Silverado 1500 4.3 Liter. 4 out of 4 people think this is I tried the relearning but the thing wouldn't stay cold forI found the directions to clean the actuator3 ton ac unit dimensions but it assumes one knows where the heck that is? best wall ac unit you point me in the right direction? how to charge ac unit on houseis this something I can reach without dismantling the dash? I'm in a 2002 suburban--same issue as the Tahoe, Silverado, 1500, seems like most Chevy trucks over 10 years old.... 18 out of 18 people think this is Here is my situation on 2012 GMC Acadia. Tried relearn trick no change. Plenty of power coming out of vents, def both very hot and reasonably cold.I have read so much it's all overwhelming, any

easy things to try or look for? How easy/hard to change the actuator and I assume you would only need to change drivers side? Sorry everyone car newbie, I appreciate ANY feedback. 5 out of 5 people think this isMy Car is a tahoe 2009 cherlot and it 2 out of 2 people think this is When I turn the a/c on in my 2004 tahoe it blows hot air out the vent for about 10 seconds and then it goes up to the defroster and blows nothing but hotI took it to the shop to get the a/c charged and they said it's already charged just not switching over from heat to a/c. Do I have to replace the air Describe your project and send it out to our top rated service providers.          No membership or credit card requiredGet StartedNo thanks, I'm not quite ready.Your car’s heating and cooling system operates using a few basic principles and some pretty rudimentary physics and chemistry concepts. However, that same system is constructed out of so many components that are buried within the hood and bowels of the vehicle that it’s sometimes difficult to know what may actually be causing a malfunction or performance problem.

Because it is so difficult to see every little thing going on with your car’s heating or AC, the best way to diagnose a problem is to rely on your senses and trust your instincts. There are many issues you may notice related to the system’s temperature and functionality. They are the least ambiguous to recognize as heating and cooling problems because they include things like the AC not blowing cool air when turned on or the heater not actually doing anything to warm the car when activated. The most common reason that a car air conditioner in otherwise good shape would start to blow hot or temperate air that is clearly not cooled, is due to a lack of coolant. Most often this means Freon, or whatever refrigerant your compressor uses to evaporate heat, has depleted. If your coolant was recently filled, revisit the shop that did the recharging to see if anything was overlooked. However, if you can say for certain that your level of coolant should be good, but you see that it now isn't, chances are you have an actual leak.

If you have a leak, simply recharging the AC system won’t fix anything. Most of the time, your problem lies in at least one of the three big components or your AC system: the compressor, the evaporator, or the condenser. It also has a small metal can containing desiccant, which should be changed whenever the system is opened. The components are in different locations in the car, so there really is no such thing as replacing the whole air conditioner as many people think they have after a major repair. Depending on the vehicle, there are several feet of hard and flexible lines that can become damaged and cause a leak. The best thing to do now is to have it evacuated and recharged with the addition of dye to aid in finding and sealing the leak. WARNING: It is especially important to deal with any electrical problems that may have occurred if there is a leak. Any fluid leak in your car's engine or electrical system can be dangerous and lead to larger problems. On the other side of the coin is heating.

A malfunctioning thermostat could be the reason that your car is not heating up. For example, if you’re driving on a particularly cold day and the temperature display in your dashboard claims the motor hasn’t reached its operating temperature, it means your thermostat is stuck open. You can further test for this issue by seeing if the ventilation blows heat when the car is idling but not when you’re actually driving. By opening and closing, the thermostat helps keep the engine at correct operating temperature. When it goes bad, it will either stick open or closed. If it sticks open, your engine will be slow to warm up and won't stay at operating temperature. If it were to stick closed, the car would overheat because the coolant can't flow to the radiator. Thankfully these thermostats are both cheap to replace and easy to access physically within the vehicle. Another issue that could leave you without car heat during the winter months is the heating coil, even if you’ve already flushed it out.

Since turning the heater on removes heat from the cooling system, it actually cools the engine. Often, heater cores plug up again even after they are flushed. if it goes away, great. However, it may only be temporary. If it’s being particularly stubborn, there are products that claim to help flush cooling systems that you may want to try. Even when your vents are actually blowing cold air properly, if you hear something like repeated or intermittent clicking, it could indicate a problem. The air conditioner dries, as well as cools the air. This allows it to absorb the moisture (fog) as it blows over the glass and clears the windshield. The clicking sound is a magnetic clutch, which allows the compressor to run or be turned off. The high or low limit switches usually cause the cycling of the compressor. These temporarily shut off the compressor to prevent damage to it. If this clicking and stopping occurs when the defroster is used as well, your problem is likely related to low pressure in the component.

You should take it to a specialist and get a full diagnosis. These symptoms are easy to spot, as they usually affect what you see and do in the car’s cabin, but the solutions aren’t always straightforward If your controls are unresponsive and won’t switch between vent or defrost, for example, but the system is still functioning and blowing cool air, you need to find a way to reset the climate control head. It involves pressing and holding certain buttons, though the specifics vary from vehicle to vehicle. Try calling the local car dealer for details or consulting an online manual now that you have a specific goal. TIP: If you’re concerned that a local dealer won’t want to give you such technical information over the phone when you have no intent of buying from them, tell them you are a tech from another local dealer working on a used car. If the system is functioning but your HVAC control speeds aren’t working, or if you’re unable to cycle between the “1” and “2” settings, it means your resister stack is bad.

The blower motor resistor is located on the passenger side, under the dash. You need to remove the closeout panel under the glove box. Look up in there and you will see the blower motor, and just over and off to the left you will see the blower motor resistor. Two or three screws secure the heater box - they are 5.5mm (7/32). If your air conditioner stops working and you’ve already checked the compressor and recharged the coolant, it’s possible you may notice a colored discharge, sometimes blue or green. Unfortunately, this means you are leaking refrigerant from somewhere. Do not be alarmed by the color. It’s likely just a UV dye that has been intentionally added so that you could detect leaks more easily. Alternatively, you may witness strange things being discharged inside the vehicle as well. If your vents ever start to blow out a white mist or vapor, check the vehicle’s undercarriage after you turn off the car from your drive. The mist you’re seeing is water vapor, and if the under carriage is dripping water, what you’re witnessing coming from the vent is essentially the cooling system making its own miniature clouds.

If there is no water dripping underneath, then it means your drain tube is clogged and condensate is accumulating in the heating and air box. If you unclog the tube, the clouds should go away. An air conditioner giving off a stench of syrup or hot antifreeze should be a tip that there’s either mildew on the evaporator or something wrong with your heater core. An additional test you can run to be sure is to see if your windows fog up especially easy while you’re driving at night. Quick-fogging windows coupled with the bad smell mean it’s a problem with the heater core. They make a few chemicals that can be shot in there. A spray of bleach will work, also. The hardest thing is getting access to the core. You may have to cut a one-inch hole in the housing to get a good shot at it. Just make sure you know where you're drilling and stay well clear of the core. A little AC tape will cover the hole afterwards. Once you kill the smell, you can prevent further mold by turning off the AC and having the selector set on fresh air, not recirculation, with the blower on high.