99 Yukon AC is charged, compressor turns on, but no cold air!

[BDog21]

I have a 99 yukon with the rear ac controls i just bought the other day and i noticed the ac didnt work but it all looked in good shape so i went and bought 3 cans of r-134a to refill it, filled it according to the instructions on the can, and it would only take about 3/4 of the first can, the ac compressor clutch will engage and it builds pressure, but i get no cold air from the vents. i then remembered the rear ac control so i turned that on to high and it pulled just a little more from the can and now the rear ac gets nice and cold, but the front still the same temp. any ideas where to look next?

sorry if this is the wrong forum but i didnt know where else to put it. and thanks in advance for your guys help!

 

[BDog21]

...nobody?

 

[BDog21]

damn...still not a single reply? not even so much as a "sorry i cant help ya" or welcome to the forum or anything? damn what a friendly welcome group of people you are...

 

[Ceejkay]

welcome to the forum. a/c problems are difficult to trouble shoot online.. if you have solid cold air coming from the rear, first suggestion would be freon. but since you already did that next step i would do is http://www.tahoeyukonforum.com/forum/showthread.php?t=29095 cleaning out your coils under the dash.. if still no dice, have the system properly evacuated and change the front oriface tube.. that will get you started but if the tube is clogged expect to change a compressor in the not to distant future..

Also if you havent noticed most of the threads asking for help are in the general section.. people visit that section a little more frequent than interior. people do have lives in the middle of summer and arnt on the forum everyday, so i wouldnt expect a 100 replys on a friday night and saturday

 

[BDog21]

thank you very much for the reply i will try those things you mentioned. And sorry i realize people have other lives too and was mainly just trying to bump the thread, now re-reading it, it does sound a bit harsher than i intended

 

[SunlitComet]

is the orifice tube installed and not plugged?

 

[83 Bimmer]

Does any air come out at all or is it just warm air?

I would definitely take it to someone who has an a/c machine so they can properly evacuate the system and recharge it with the correct amount.
I hate using those cans of refrigerant that you pick up at the parts store because you have no idea what's left in there and you can't apply a vacuum to the system to get rid of any air that is left in there.
Also hooking it up to an a/c machine will tell you what the pressures are on the high side and low side which is a huge help knowing when it comes to trying to diagnose an a/c system

 

[cowboyzr2]

Just because it has just enough refrigerant to trigger the low pressure sensor and keep the compressor running doesn't mean it has enough refrigerant in the system to really make your air cold. Does it start to cool at all when you're driving?

Either way, x2 on the "DIY" kits. I've got to where I've done so much work on my AC systems I just went ahead and bought a vacuum pump and manifold gauge set. They paid for themselves the first two times I used them.

Probably the best thing to do would be vacuum your system down, test it for leaks and properly fill it to the correct specifications.

ALSO - With rear AC it takes a LOT more refrigerant than a standard truck with only front AC. Once I charged mine, it read that it was fine but I wasn't getting any cool air. After running it a while I checked it again and it was low. Once I got it charged to the right specs, mine is a meat locker in the summer. Best AC I've ever had.

 

[SunlitComet]

Uh test for leaks with it under pressure with some uv dye added. Don't vacuum it down and leave like that to test otherwise if it is leaking you will just suck in more moisture from the outside air. or get a electronic detector. those things can spot the most minute leaks.

 

[arsonfnder]

sorry to resurrect this old thread, couldnt find my problem so here it goes, the ac blows very cold but not every time does it come on when i turn the dial, the ac light comes on, fan blows hard but no cold air, until several minutes up to 10-15 of dirving???