My wife's 2010 Rav4 has an AC problem. When I turn it on the AC little orange indicator lite will start to blink after a few seconds and no AC operation. I checked and i think it is full of freon, or what ever the new stuff is they put in now days. If I pus the AC button repeatedly, the air will get cold but it will not stay on. someone said it may be the run sensor? Where is this sensor and how do I check it? And what else can I check? Thank you.