VERY INTERESTING. I took out the Fram cabin filter and started it up, and I only heard the 'hissing' for 1-2 seconds, and the air is ice cold again! When I took out the filter I noticed there is a permanent dark grey filter with a wire mesh covering, that looks like this Fram filter with the carbon in it, just to the left of the replaceable cabin filter. Does THAT one have carbon in it and other things for filtration? Anyway, I put the filter BACK in this time I THINK the right side up. I THINK I had it in upside down, not sure, but the arrow on it was now pointing up. The hissing still stopped at like 3 seconds. BUT with it totally out, glovebox back in, and radio on, I hear it for 1-2 seconds and it is ICE cold. I put a regular room thermometer, you know glass with that red water/fluid in it, and put it in front of the middle vents and it goes to 58 degrees in 1 min. THATS cold...even for me! Is that about right? Has anyone else done that 'test'? And I get a nice puddle of water under the car, from dehumidify the air, and that has been missing for the past month to.While I still will take it in on Mon. to have it looked over, and maybe to demand to replace that access. belt, IF nothing is wrong with the A/C, other than it needs a cheap replacement filter for some reason. I am doing all this as preventative maintenance to keep it running, that is why I am keeping it, not because I love the speed and grace of the car. Its paid for, it has 28K miles, its still showroom shiny new. So....any opinions on what I just did, and could it have been THAT simple? Because it is ICY cold now, and with the 'normal road noise' and radio on, I probably was hearing the 1-2 second hiss, and ignored it, as normal noise, because it isn't a Lexus stuffed with sound deadening pads or whatever makes high end cars so quite, it is a cheap car, and it took the 10-15 second hissing and lack of COLD air for me to notice it ??? I am just hoping this is the fix, and maybe I was pressing on a vacuum hose of some sort, or a refrigerant hose, but I couldn't find one behind that filter. So...any opinions would still be great, esp. has anyone tested how cold the air is with a thermometer in a min? I got 58 degrees, .....anyone else?