Mechanic said system was 1 lb low? Based on what? You can hook up gauge set and see pressures. If low, you can try to add Freon. If pressures improve then it might be quick/temporary fix. A pro would evacuate Freon and measure amount. Check for vacuum. Then add proper amount back.
a system that has same pressure on low side and high side could indicate a bad compressor. If compressor is actually running.
a static system where compressor is off will have same hi/lo pressures.

 

Hi folks, the issue that you guys are having with AC that only works when the engine RPMs are up is due to a faulty compressor scroll valve/control valve. The scroll valve looks like this:






This sits inside the back of the AC compressor, held down with two bolts underneath a small mounting plate. It seems to get clogged or just stops working for whatever reason, with the lack of cold air at idle RPMs is the biggest tell that you have this problem. Luckily the valve is available new from a number of suppliers and is fairly cheap, around $20-$30, ie:


https://www.ebay.com/itm/133994508729

https://www.autozone.com/cooling-hea...270/966037_0_0

I'd look for a kit with that green gasket included. Our Vue's use the same valve that was found in a number of other vehicles that had the same problem with the same fix (Ford 500s, Jaguar S-types from the mid-2000s, Ford Escapes etc), so perhaps your AC mechanics would have heard of this fix with those brands.

TutorialGenius on youtube did a comprehensive video on how to replace the valve if you want to tackle it yourselves, it's not the most difficult job to do but you do need to evacuate the system and fill it up again to complete the repair:

 

Thank you Redview!

 

Sticky time!

Now also located in general Tech section as a sticky.

 

That would be fine if this vehicle used that type of compressor but it don't.