I'm trying to find a vacuum leak in my hvac air lines. I was yanking on this one and the small line snapped. Good God it's behind the firewall. What did I just do?
2001 XJ

 

If that is the case, it is the vacuum source for your HVAC controls

 

I found the vacuum lines behind the glove box but I can't seem to reach to the firewall. I guess I could get a new hose in the opposite direction, from the bay? Thinking out loud but feedback would be appreciated.

 

Is there a little bit from the engine bay side to grab onto?
Not a Jeep but my friends '04 Taurus. Had the exact same thing happen.
There was enough to grab onto and enough slack to pull some of it out.
Then came the problem of how to reconnect the 2 pieces.
I happen to have this lying around. Used one to cap off the rear diff breather in the uni-body.


I ran a long line up front and put it next to the front diff breather in the engine compartment.
Which is why I had it in the first place.
Anyway found one of them was the perfect diameter for the small line in his car.
Cut the closed end off, inserted both lines, and put some electrical tape on each side for the hell of it.
Everybody sing along now. M-I-C-K-E-Y M-O-U-S-EEEE.
Hey it worked. LOL.

 

If Ralph's suggestion isn't feasible, I hate to be the bearer of bad news, but that line runs right into the HVAC box and you would have to remove it completely. Not a hard job,but time consuming. On a positive note, if that thing came out like that, I suspect you may have found the source of your vacuum leak. It had to already be split or broken.

 

NO IT DOESN'T! It runs to the heater control panel. If you can fish it thru the firewall hole, you can attach it to what's left of the original tube right at the panel with a short piece of rubber hose over it.

 

Well, my idea was to pull some slack out through the firewall and trim the old piece and reattach it with some rubber hose. I also cut it at the glove compartment to give myself more tube

to play with and I'd then reattach it again with more rubber hose. While pulling it from the firewall everything was going well until about 5 inches of tube came out. It's as if I pulled it off another connection point deep in the dash.

This is a picture of behind my glove box. I can see where the black tube eventually makes it's way to my control panel but I cannot for the life of me see where the point is that the firewall and this tube meet. I fear my rubber hose is too flexible to be fished through. I'll have to find a more rigged tube or maybe a metal wire to help me locate the path...

 

Maybe this will help you figure out the path of that plastic vacuum line. It appears it takes a awkward path in a channel towards the drivers side before it turns and goes back to the passenger side to join a bunch of vacuum lines.

This pic is compliments of 5-speed who posted it in a thread I had about where does that line go? I just copied and pasted it.

 

Oh, eff. I'm screwed. No way I'm getting that fixed without pulling the dash....

 

Maybe....maybe not. I am close to being in your position. The vacuum line broke about 1 inch inside the engine bay and I was able to attach a coupler to it to make the connection.

But my plan if it breaks again is to run a line from the engine bay through the firewall at the passenger side with the wiring bundle that goes through there. Attach to the first vacuum bundle "joint" under the edge of the dash just to the passenger side of the console and replace the black line in that bundle.
I don't know this for fact, but I can't see them running a vacuum line into the AC/Heat unit without going to the controls first. Can't say for sure it would work, but I think it would work. The vacuum line is pretty flexible new and can be obtained at auto parts stores, I saw it at Oreilly's. A PO to my Jeep had ran
some extra wires through the wiring bundle that I left for "pull tapes" as needed. So getting through there is not a problem. I am like you, I didn't want to take the dash apart for a frikken vacuum line.

I have replaced the heater core/evaporator in another Jeep I owned, it was doable but a royal pain in the butt.

Good Luck!