Front A/C not cooling

[chuck's]

My 99 suburban will not blow cool air from the front a/c.I tried the rear a/c and it seems to be working.Would a low charge of the a/c create such a problem?The system was recharged in August of 2003 due to a leak in the rear a/c line.The clutch comes on when the a/c button is pushed,but it is like the temperature control is not responding or the thermo coupling valve (I think it is called that) is not opening to let the freon through.Any help with this would be greatly appreciated.Summers coming and it's going to be hot!!!! Thanks.
chuck's

[84fiero123]

when you turn the ac on can you here the heat door closing? turn heat on then off to see if you can hear heater core door closing when you turn ac on. it may not be closeing and you are running the heat in the front the same time thats why there is no ac in the front and you are getting it in the back. just an idea, guess, best guess if not that it could be in the ac system it self.

[777stickman]

Chuck's: Try this: A/C off, engine at operating temp. Turn the front fan on and switch from cold to hot on the temp control. You should feel a big temp difference. If you don't it's a door control problem. The A/C doesn't know the difference between front or back. It supplies freon to both at the same time.
My Sub is an old style '99, aka '98, and the temp door is controlled by electronics.

Let me know what happens and I'll try to help more.

[chuck's]

Thanks for the help.I took the vehicle to an a/c specialist and it appears that it may not be a very serious problem.From preliminary observations it appears that the expansion valve is not letting the high pressure freon pass through to get to the accummulator.I was told that if the compressor cycles properly then it wont be an issue with the charge in the system.Basicly the valve appears to have gotten plugged.I do hope that there won't be any metal particles in the screens in the valve assembly.If there is ,then my luck may have run out.I will keep everyone posted as to the outcome.
chuck's

[chuck's]

I got the a/c fixed.It turned out that it needed to be recharged.Suspect that there is a minor leak,but nothing showed up when the system was pressure tested.Good for another two years.
chuck's

[scoteric]

I had the same problem after replacing the rear line. I finally found a slow leak on the high pressure valve where you hook up the gauges. Slowly open the cover and see if you can hear a slight hiss.

[scoteric]

I had the same problem after replacing the rear line. I finally found a slow leak on the high pressure valve where you hook up the gauges. Slowly open the cover and see if you can hear a slight hiss.

[chuck's]

I took your advice,scoteric,and unscrewed the cap on the high pressure valve and it was hissing.Also noticed oilly residue on and around the cap.It definitely is leaking.Back to the repair shop to get it checked out.
chuck's

[chuck's]

Rplaced both valves for the a/c,recharged the system and will monitor the valves.I'm glad this fixed the problem.
chuck's

[yuckem1]

I'm having the same slow leak from the high pressure valve. Is the valve replaceable and does it require a special tool? Thanks

[chuck's]

The high pressure valve is replaceable.It unscrews from the line.There is supposedly a special socket to fit on the valve body,but we just tapped a six point 9/16 box end wrench on the valve and removed the valve.Since the valve is made of a softer material than the wrench,it formed to the wrench.We installed the new valve with a pair of common pliers.The valve has an o-ring on the outside of the body.This does the sealing for the threads.
chuck's