BMW Repair: A/C, intermittent operation, cold ac

Question
I have a 2000 323i. I was sitting at a stop light the other day, with my ice cold AC on. The air stopped blowing from the vents. I rolled through the stop light, about a half block later, and the air started blowing again, still ice cold.  A week later, the air stopped blowing, and it seems to be permanent. I am enclined to think this is a resistor, or a ground, being that A motor would fail, or not, it wouldnt have intermittent operation. Is my assumption correct, and how do I find/fix this issue?

Answer
Well it is possible for the fan motor to quit working.If you have climate control it too could cause the problem as you mentioned a bad ground.Does the fan work all the time in the heat mode?I would be checking the grounds and check to make sure there is power going to the motor.