Need your help, I have a nissan xterra 2000 with 98000 miles.When the a/c is turned in, it comes on and goes off on it own, I took it to a mechanic and he told me there is a leak in my a/c line. My questions is we low freon due to the leak, would the a/c come on and off (when it works it works perfect but than it just turns off and starts to blow hot air), and if it is possible that my a/c is misehaving because of the hose, can I change it my self? I would reall appreciate any help. Thank you in advance.