Air Box Flapper Vaccum Line

[Hoolio]

I pulled my airbox because I was debating doing the small airbox mod. After reading all the positive and negatives I decided against it and decided to just purchase a BMC street filter. Problem is when I pulled the airbox the vaccum line for the flapper line was not connected to the actuator nor could I found it. The flapper was wide open when I removed the stock filter. Does anyone know where this line originates? I've looked all over the engine compartment and I don't see an unused vaccum line.