3.4l vacuum question

[Bad_Vision]

hey guys im looking to find were the 3 way vacuum line goes the one in the back of the engine near the coolant outputs.
its a cross over from one side of the plenum to the other but i cant find were the single out goes to?

 

[Bad_Vision]

its a y connector at the back below the coolant temp control valve and right next to the harness cross over

 

[denvertoyota]

its a y connector at the back below the coolant temp control valve and right next to the harness cross over

It goes to the IAC Valve under the throttle body