Any a/c problems on 09 aveo good pressures low side line cold but sometimes it blows cool

Reads in the red ... could mean to high or low pressure.
Explain .................................................

I'm no expert when it comes to your vehicle. However it sounds to me as though there may be a vacuum leak somewhere causing the HVAC door that controls the AC/heat to be faulting to the 'hot' side.

Drive the car up to 55 MPH with the AC on. Making sure there is no vehicles close behind you,completely let off the gas pedal and see if it starts blowing cold air right after letting off the throttle. If it blows cold, then it's probably a vacuum leak.

If it doesn't blow cold then it could simply be low on freon or a partially clogged filter in the AC line.

Hope this helps.

If the system is running right, a quick check is to see if the cold side of the compressor lines are sweating/condensation. Then most likely the system is good. The A/C filter, called a dryer, isn't changed unless you have a catastrophic compressor failure, ie lots of metal in the lines. The cabin air filter has nothing to do with the A/C system. Assuming you have a good system and not getting cool air inside the cabin. The blend door motor is bad or it could be just unplugged. These are usually locate under the dash, in front of the console, on the drivers side. Some times on the passenger side. I do many makes and models of cars, So I can't tell you exactly where yours is. Hope this helps.

I like that you were knowledgeable to check both coolant lines tells me you are getting hot coolant through the heater core next thing to check will be the blend door on the inside of your vehicle. The blend door is a door that switches from cold air duct to heater duct depending on what you are using at the time. If it is stuck on the cold air duct you will not get any heat sometimes these doors are vacuum actuated and sometimes they are electrically actuated most the time you are able to see the movement of the motor from inside if you don't see any movement but you hear it move chances are it is the door blend I hope this helps.

First of all get the Freon level checked, if Freon/ refrigerant is low then it can cause this problem.Wen Freon is low it takes time to cool.--- So first get Ac pressure tested.It can be tested at any local car garage.Some times pressure will be checked OK, but still if Freon is getting clogged in the line/ tube then it will not reach the front , but reaches rear then front will not cool, but rear will.--------

But mostly this problem is related to blend door.

If the rear is working well and front is not I would suspect a blend door or actuator issue in the front.Double check and see if you can hear anything moving when you are adjusting temperature from hot to cold.Also check and make sure the air flow moves properly from defrost to vents and floor etc.

Either a bad blend door motor or Climate Control Assembly. The A/C heater function selector switch combines a vacuum selector valve for direct control of the vacuum control motors and electrical input to the instrument cluster module.

------------

The blend door actuator is located behind the glove box.-----

To see blend door diagram for your Yukon Denail, click the link below :---

http://howtobyme.blogspot.com/2011/08/where-is-blend-door-actuator-located-on.html

------------

This will help.Thanks.Helpmech.

80lbs on the low side is WAY too much if the clutch is running, the high side you should see 125-150ish, the low 30-40. I would feel the lines (the bigger line going into the firewall to see if it is cold when your pressure is right) if so suspect a blend door motor which controls the hot and cold switching inside.

common problem, you have a bad blend door motor, also be careful sometimes the blend door breaks at the end that goes into blend motor if is then blend door has to be replaced also w/motor hope this helps, ive done a lot of these, good luck.

is the compressor turning on? when you turn thwe a/c? on,
and also locate the low side line on engine compartment and feel if is cold, if it is, then your blend door system is not working,
the blend door does control the cold and hot air coming to engine.

Many auto cooling/heating systems use a "blend door" which mixes both hot and cold air to provide air at the temperature selected with the temperature control. When the temp control is in the full cold position, the blend door moves to a position which allows only cold air to pass into the cabin/passenger compartment.
That blend door is generally operated with engine primary [unmodified intake manifold pressure] vacuum. IF there is a leak in the primary vacuum line system, then at low engine RPM the leak may bleed off the vacuum necessary to hold the door in the cooling position. Then when driving, the vacuum will be much higher, "over riding" the leak, and allow the vacuum motor, which operates the blend door, to hold the door in the proper position and provide only cold air to the cabin/passenger compartment.

There is only one A/C system split into 2 zones. Check the blend door actuator, it may have failed in one position or something may be jamming it. Also check the control panel in the dash, My 98 yukon did the same thing, no matter what temp you selected for the front it would blow at about 70 degrees. There is a circuit board in the control panel that gets corroded and one of the circuits controls blend door operations. Have a look.