The AC in my 99' Yukon quit working last Jan. Pep Boys recharged it and put a dye in to find leaks. It worked fine all year until last month when I would turn the ac off because the temp dropped outside. In Florida it gets cold one day and it is 85 the next. After cycling the systen on and off a few times it quit working. The pressure was low and I bought a recharge kit. The air was cold for less than one day. Could there be a leak that is triggered when ac button is turned off and on?