yea its suppose to shut off when the car is off....some cars, the fan runs for a few mins after you shut the car off but i know mine doesn't not sure if yours does.....but the guy def messed up the wiring somewhere when he did your system.....where did you go to put the alarm in? if its a reputable place i'd take it back and have them back track and check their wiring to make sure they didn't splice into something they shouldn't have or disconnected something and forgot to reconnect.......having your fan act up and your climate totally gone in one day after it was working perfectly is highly not a coinsidence