Need help locating end of vacuum line - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Hi all. I know the subject of vacuum lines has been covered pretty extensively here but I haven't been able to find anything related to my specific problem. I have an 02 Boxster S, 3.2L 6 sp man with the Aerokit pkg, purchased in 2006 and as far as I know all components of concern here are stock. Anyway, I've been replacing all of the small 1mm dia. vacuum lines as they've become brittle over the decades and were starting to crack. I'm down to my last line, but I can't tell where the terminus is on it. The connection that I can see is to a change-over valve which in turn is connected to the vacuum canister. Going out from the CO valve the line makes a turn over the top of the transmission (blue circle in pic), and then after a few inches disappears beneath the heat shield material mounted above the transmission/exhaust, and that's where I lose it. I guessed that it re-emerged someplace in the trunk, but after removing the carpet/padding in there I can't see anything that looks like that line so I was probably wrong about that... I've heard that the Tiptronics use vacuum lines for cooling, but again this is a manual so that wouldn't make sense to me. And as far as I know I don't have a valved muffler. If I tug on the line, there's resistance, so it's definitely connected to something and not just dangling loose under the heat shielding. What could this possibly be connected to? This line previously cracked and I have a cheap-o Dorman repair sleeve that fixed it (red arrow in pic), which seems to be doing the job ... idle is good and no P1128/1130s being thrown. But I'd like to figure out where the line ends to decide if putting a fresh one in is worth the work. Thanks in advance!

My guess is that it had a valved muffler in the past and the vacuum tubing was not completely removed. I had a very similar set-up that was also on an '02 S model with Aerokit that still had the Porsche Sport Exhaust. Take a look at the wires connected to the change-over valve. Are they integral to the engine harness or do they look like an add-on? Can you trace where they go to? The vacuum tubing is probably tied down in back even if it is no longer connected to anything. Whatever it was for it looks non-standard and is likely unique. I'm pretty sure the change-over valve is defaulted closed so that line does not present a vacuum leak.

Thank you very much for those suggestions 78F350. The power lines for the c/o valve in fact have their own hole poked through the harness firewall grommet and then head straight to the relay box on the far left of the trunk. So it seems that you were right about this being for a previous valved muffler or some other accessory that was removed (or installation started but never finished). I double checked that the c/o valve defaulted to closed by removing one end out of the Dorman sleeve and diving ~50 miles ... smooth running and no codes. And good to know that a vacuum line has already been plumbed-in if I ever decide to install PSE. Thanks again!