I know of an awesome shop that could test & fix it for you. Their prices are very good & the tech is a good friend of mine. He can fix just about anything, hehe. Only once have they fixed a customer's A/C & literally had it blowing snow through the vents. To explain a bit further on that, what had happened was that there was a leak in the A/C line & the condensation was being blown into the vents causing it to snow, LOL. I still cannot believe that the customer complained about that in this Texas heat, heh.
Anyway, the place is called Don's Automotive & Collision. Just ask for Jon, who is their auto technician there. The place also does dent repair, paint jobs, etc. They are one of the only shops that I trust. On my old car, they pulled every dent out of it & did a custom paint job as well for a nice price & it was perfect
The shop is located on the SW corner of Kellar Springs & Old Denton Rd. in Carollton.