On my '99 XJ I am only getting air blowing out of the defrost, no matter where I put it to on the ****. Is this a vacuum leak causing this?

 

yes, vac. leak for sure. Check all the connections near the batt.

 

Yes, the blend door inside the heat/air system are vacuum actuated. A broken of disconnected vacuum hose will cause it to only blow fron them derost. Also check the lines going to the vac resevoir on the passenger side behind the front bumper.

 

Wow I was about to ask this question mine just on a 91

 

Thanks for the replies I will check on those lines tomorrow.

 

Also, make sure there are no cracks in the vacuum ball. I was told that if the vacuum ball is cracked, then when you accelerate the heat goes from vent to defrost. I supposed if the crack is bad enough, then you'll just have defrost.

 

cool, thanks I will check that too this evening when I get home from work.

 

I have a question reguarding this same issue...my cherokee is having the same problem, however the cruise control does work. If the cruise works does this mean it is not a vaccum leak? becuase i know that cruise is vaccum operated as well. Woulldnt one leak disable both, or is this not ture.

 

Bingo.

 

my 97 is stuck on the defrost setting too, it really sucked this winter i missed the floor setting. i pretty much went through the entire jeep and couldnt find a vacuum leak. guess i could start the search again now that its warmer out.

 

Two different vacuum circuits. that is why your cruise works.