Heater hose question
 

I'm trying to replace the heater hose in the trunk area (89 911)that connects way deep in the drivers side area under the cowl. I can see where it connects at the other end when I remove the cardboard cover in front of the wipers area. I can't see how it connects down below. Does it go through the firewall and connect inside the passenger area or does it connect inside the trunk? Any help would be appreciated.

A picture would really help since there are several ones.