Air conditioning woes

[Badluckchuck]

I just bought a used 2007 Yaris. The car dealership was great they gave me a 30 day or 1000 mile warranty, which unheard of. Well first day I drove it I noticed I had no A/C.
So I called them and they said bring it over and they would charge the system. When they hooked up their gauges it was over full so they backed it down and refilled it. This did nothing, so they said go to our mechanic and let him look at it. So, I did and he tried the same thing and again it didn't work. He said shut the car off and as he watched his gauges, he noticed the pressure had not equalized. He said you've got a bad orifice. Hr ordered me one. I returned in 2 days, he swapped them out, backed it down, vaccumed it out and recharged it and low and behold 39 degree air. Man I was stoked after all I had been driving 1000 miles a week with my windows down. So I thanked him and drove off. Well about a mile down the road I started sweating cause it was blowing warm air. So I called him and he said come on back. When I got back I told him just how it happened and then I said but as soon as i got here it was blowing cold again. He started hooking up his gauges, when he said "start it up and put it in drive and as soon as I did the compressor and fan shut off. We looked and checked all we could think of. He called his friend who is a mechanic at the Toyota dealership and he said that a new one on us. We scoured Google, and YouTube for answers and came up with nothing. You don't even have to be in gear for it to shut off, you just got to push the gear selector over and it shuts off. The mechanic hooked up his code reader and recreated the problem and it shows on and the when you move the selector over it shuts of and his code reader would show on,off,on,off etc. He says this is a first for him too. Anyone else have this problem and had it fixed or any idea what this could be and how to fix it.