I had a leak in my high pressure line and lost virtually all pressure in my system. When the A/C was switched on, there was a switch cycling noise (like a valve opening and closing) and hissing noise coming from behind the center of the dash.
I replaced the high pressure line last week and had a shop pull a vacuum and recharge the system. The system blew mediocre cold air, more cool than cold, but was better than nothing and I hoped it would get better after working for awhile...
So a few days ago the cycling and hissing noise starts back up behind the dash. I took a pressure reading on the system thinking I had another leak but the pressure is high (~150 psi @ 100 degrees outside temp).
The only thing I can guess at from reading is a bad thermal expansion valve? Anyone else have a similar problem and have luck fixing it?