Vacuum Reservoir
 

So...what exactly does this vacuum ball do that's behind the bumper? I've seen it is for cruise control and the heater vents or some crap but what else? Mine seems to have taken a trip somewhere without telling me.

The xj is driving just fine without it but curious what exactly it all deals with.

I don't know exactly what it does but mine seems go have taken a vacation as well. I had a trouble code that Said I had a vacuum leak but now I don't. And engine performance does seem to have taken a crap.

Well maybe they ran off to Mexico together then. It has to be there for a reason but it's running fine without it so I don't know lol.

Well I'm pretty sure mines in a mud hole somewhere along with my driveshaft.

The vacuum ball is responsible for your HVAC and cruise controls. And depending on the year of your XJ/MJ, it also serves to engage/disengage the hubs for 4x4.

I don't have cruise control nor do I have any problems with my 4x4 engaging.

What year is your XJ? You can fill out your info in User CP :thumbsup: Looks like you have a newer model in which case you do not have the vacuum-actuated 4x4 system. Can you adjust your vents from dash/floor/defrost?

I have a 95. 4x4 engages just fine, heat works just fine, run just fine. I haven't noticed anything different since the ball went on vacation.

The vac line to the T-case switch ,(on Comand Track), actually comes off the big line TO the ball, then the little one from the ball let's the cruse and heater stuff work when your manifold vacuum crashes when you have your foot in it.

If your balls took a hike you probably have a big vacuum leak down there somewhere...sucking in lord knows what Btw....

It's a "buffer", so you always have vacuum....

So can I just cap the end or should I replace the ball and relocate it?

No I can't adjust it.. Ha it's stuck on defrost. I figured it was from a actuator or something taking a crap and how do I do that? Ha

Stuck on defrost is a good sign of vacuum leak. All the actuators use vacuum to move the vent doors.

Ahhh. Well damn. One more thing to fix then.

I'd at least plug the big line till I found another ball. I suppose hooked to the small line might at least be interesting. The controls should change when you gas it....no idea what that might do if you had cruse control!