Im in the process of replacing my heater core to get that working n everything is going smooth then i stuble across thiss guy not being connected to anything. Its on the water ****. Does anyone know where this plugs into the vacume line meaning and could this be why my car was only blowing out cold air?

 

Look for the other end. Really... there's got to be another open vacuum line floating around. I don't have a Haynes manual right in front of me, but I imagine you can find out pretty quick by looking in there, or the FSM.

 

part of that climate control crap perhaps?