My 2004 A8 is having a weird AC issue. The air stops coming out of the front vents intermittently. When you start the car, the air would not blow. Then when you are driving, it will intermittently blow on for a few secs then turn off again. Weird part is that sometimes the front vents will not have air coming out but the rear vents will. My mechanic has swapped out the blower but it didnt fix the issue. Now they are fixing some sort of board or resistor. The blower cost me 240 bucks and now this new part will cost me 190. And they are not sure if it will even fix the issue! Any ideas on what it could be? Btw, when it does blow, it blows cold air like I have it set to. Thanks for the ideas and help!