i live in florida and every morning my windshield fogs up when i have the a/c on. i tried putting the defrost on but it doesnt help. i just realized my heat doesnt work. i take that back, sometimes it works. it's a 95 LS. all my vents switch and i can control my fan speeed but the temperature only gets as hot as outside temp. a couple times i've gotten real heat. any thoughts?