sounds like the air-conditioning expansion valve is probably not working correctly here is a way you can fix your air conditioning:
Realize that auto AC is basically a refrigerator in a weird layout. It's designed to move heat from one place (the inside of your car) to some other place (the outdoors). While a complete discussion of every specific model and component is well outside the scope of this article, this should give you a start on figuring out what the problem might be and either fixing it yourself or talking intelligently to someone you can pay to fix it.
Become familiar with the major components to auto air conditioning:
the compressor, which compresses and circulates the refrigerant in the system
the refrigerant, (on modern cars, usually a substance called R-134a older cars have r-12 freon which is becoming increasingly more expensive and hard to find, and also requires a license to handle) which carries the heat
the condenser, which changes the phase of the refrigerant and expels heat removed from the car
the expansion valve (or orifice tube in some vehicles), which is somewhat of a nozzle and functions to similtaneously drop the pressure of the refrigerant liquid, meter its flow, and atomize it
the evaporator, which transfers heat to the refrigerant from the air blown across it, cooling your car
the receiver/dryer, which functions as a filter for the refrigerant/oil, removing moisture and other contaminants
Understand the air conditioning process: The compressor puts the refrigerant under pressure and sends it to the condensing coils. In your car, these coils are generally in front of the radiator. Compressing a gas makes it quite hot. In the condenser, this added heat and the heat the refrigerant picked up in the evaporator is expelled to the air flowing across it from outside the car. When the refrigerant is cooled to its saturation temperature, it will change phase from a gas back into a liquid (this gives off a bundle of heat known as the "latent heat of vaporization"). The liquid then passes through the expansion valve to the evaporator, the coils inside of your car, where it loses pressure that was added to it in the compressor. This causes some of the liquid to change to a low-pressure gas as it cools the remaining liquid. This two-phase mixture enters the evaporator, and the liquid portion of the refrigerant absorbs the heat from the air across the coil and evaporates. Your car's blower circulates air across the cold evaporator and into the interior. The refrigerant goes back through the cycle again and again.
Check to see if all the R-134a leaks out (meaning there's nothing in the loop to carry away heat). Leaks are easy to spot but not easy to fix without pulling things apart. Most auto-supply stores carry a fluorescent dye that can be added to the system to check for leaks, and it will have instructions for use on the can. If there's a bad enough leak, the system will have no pressure in it at all. Find one of the valve-stem-looking things and CAREFULLY (eye protection recommended) poke a pen in there to try to valve off pressure, and if there IS none, that's the problem.
Make sure the compressor is turning. Start the car, turn on the AC and look under the hood. The AC compressor is generally a pumplike thing off to one side with large rubber and steel hoses going to it. It will not have a filler cap on it, but will often have one or two things that look like the valve stems on a bike tire. The pulley on the front of the compressor exists as an outer pulley and an inner hub which turns when an electric clutch is engaged. If the AC is on and the blower is on, but the center of the pulley is not turning, then the compressor's clutch is not engaging. This could be a bad fuse, a wiring problem, a broken AC switch in your dash, or the system could be low on refrigerant (most systems have a low-pressure safety cutout that will disable the compressor if there isn't enough refrigerant in the system).
Look for other things that can go wrong: bad switches, bad fuses, broken wires, broken fan belt (preventing the pump from turning), or seal failure inside the compressor.
Feel for any cooling at all. If the system cools, but not much, it could just be low pressure, and you can top up the refrigerant. Most auto-supply stores will have a kit to refill a system, and it will come with instructions. Do not overfill! Adding more than the recommended amount of refrigerant will NOT improve performance but actually will decrease performance. In fact, the more expensive automated equipment found at nicer shops actually monitors cooling performance real-time as it adds refrigerant, and when the performance begins to decrease it removes refrigerant until the performance peaks again.
No your thermostat is stuck open which will not hurt the engine. but needs to be replaced, the thermostat is what allows the engine get up to operating temp. before allowing water to flow through the radiator and when it is stuck open it doesnt allow the engine to reach operating temp. so the heater never gets hot. I hope that helps you out.
Sounds like the air "blend" door might be inoperable. This door opens and closes a specified amount to regulate the amount of either cooled or heated air, as requested by the climate control unit. If the door is continually in the position which is bypassing the heater core (cold setting), the air will not get warm regardless of the condition/operation of the heater core. I'd suggest having this component checked.
will the air flow switch from floor to the mid to defrost? if so then we have a problem with the tempature door actuator. easy to replace just in tight place. Keep me posted for more help or if this was any help thanks
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Jun 25, 2009 - Hot air from vents-driver side and cool air from vents on passenger side. ... The driver's side vents were blowing out hot air, and everything else wasblowing cold. ... you'll literally have to restart your tahoe/yukon at every traffic light to keep cold air coming ... I was also getting air only out of the defrost vents.
? 3:14
https://www.youtube.com/watch?v=5lnd8UNcx6M
Aug 3, 2013 - Uploaded by South FL Mud Club
Suddenly hot air started blowing out the air vents only on the drivers... ... is a very helpful video ,I wondering if this part number apply for my 04 chevy tahoe? .... I have cold air out of thepassenger side, but warmer air out of the driver's side. .... 2003 Tahoe No Rear Heat Fix, Suburban, Yukon XL Repair!
Driver/passenger air vents blow hot then cold when using A/C. Back to cold when you restart the vehicle. Upvote (35) ... 2003 Chevrolet Tahoe ... I have a 02 Tahoe ,and the heat system is working only on the ceiling side of the car when turn.
? 2:25
https://www.youtube.com/watch?v=Eqf-H3COtSo
Nov 4, 2013 - Uploaded by 2CarPros
My problem in my 2004 chevy tahoe is that it will not blow out of the dash or ... onto the vent door gears ...
forums.edmunds.com > Chevrolet > Chevrolet Suburban
Jul 20, 2010 - 30 posts - ‎16 authors
I just don't get why that doesn't work right in the first place. ... I have 99 Yukon that has a problem with the front air. .... $55,000 for my GMC, I guess expecting cold air when we push A/C and getting 90 degree blast ... 2001 Yukon XL 1500 Front heat & air fine, rear ac blows hot as if heater is on in all settings.
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Try to back wash the heater core first if it doesnt work then its clogged up try to turn the heater on the front with the heater off for the back keep an eye on the temp guage if it goes up than normal then its clogged....
Fyi u have to run the engine for awhile with the heater fan on
I had same problem on my 2001 gmc yukon. I found leak under my water pump. I replaced it myself and the problem was cured. heater wont work because there is not enough water to be heated for the heater.
If this happens when you are idle, and then you get hot air as you drive, most likely you have low coolant and it only cycles as you drive. Get approved dextrom gmc coolat and cap off your coolant it is most likely low.
the most common problem here is a defective air temperature control blend door actuator, this is what moves the door that controls air flow across the heater core or the ac evaporator core, to replace this requires u remove the dash assembly.
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