This problem has been occurring off and on for about a year. The Heat/AC will not blow when starting the vehicle. The Heat/AC is definitely on, but no airflow at any dial setting. If you set it to "Vent", you can feel a small trickle of air coming in. Up until today, the situation would eventually resolve itself once you get going down the road. It seems like the air coming through the vent triggers something and the system will finally begin blowing normally. However, today, it never came on. No airflow even though the system was on.