Where does this thing go?!?

okay, this is going to seem like a very weird question, but i have to ask it anyways. I have a 2002 gtp and while I was trying to install m/i on the car I noticed something. On top of the s/c there is a vacuum block with three hoses coming out of it. I know one goes to the braking assistance do hicky, and the other goes to the s/c bypass valve, but where does the other one go. It runs across the firewall, under the fuse block, and into the cab. I unplugged it to see what would happen, and I didn't even throw any trouble codes and all of my guages worked just fine. So, where in the heck does that thing go? I even looked at vacuum diagrams, and it doesn't even acknowledge the existance of the tube. If anyone has any input on this little mystery I would much appreciate, even if it's just for my own peace of mind.

That should be the vacuun line to the AC programmer. BTW, usually a vacuum leak will not throw a code!

The proper term for the vacuum line that feeds the HVAC system is accessory vacuum. It looks like you did not look at the right vacuum diagram. See pic below.

http://i5.photobucket.com/albums/y186/lizzywiz/vacuum.jpg

The symptoms you will get with that specific line disconneced is improper vent control and airflow. The bottom line is it is needed and must be connected since the HVAC system uses vacuum to control the various actuators under the dash. The line enters the firewall and feeds into a vacuum distribution block by the blower motor assembly. One symptom is you will have no control over the center dash vents. Air will flow out the defrost and floor vents only.

I guess i did look at the wrong vacuum diagram. I was just really curious as to where in the heck that thing went. Thanks for the help guys. Oh, i have another question. I posted it on one of my other threads, but no one has replied yet. I am installing methanol injection on my car and i don't know which line to hook the boost switch up to. I tried hooking it up to where the accessory vacuum line was on the vacuum block but it did not kick on. If I put a "T" on the line that plugs into the MAP would that work? I am not completely up to speed on the whole roots style supercharger thing yet. Thanks again for the input.

never mind, i figured it out. i just ran a "T" off of the MAP and it is working fine. now all i have to do is wait until i order the throttle body spacer and i will be good to go. thanks for your help.

The vacuum line to the MAP sensor is correct. For example if you have an aftermarket boost gauge that is where it is connected for the best and most accurate reading.