ok heres the deal.


i have an 89 cherokee. when my ignition is in the on position i only get air from my defrost in every setting and it blows really well. now my under my understanding that is normal default setting for the blendors. when i turn the ignition on and the engine is running all the settings work fine except defrost. the defrost setting blows lots of air to the floor vents and just a tinny bit of air to the windshield???... is this a problem with the controler behind the trim and switches??? or the vaccum line? where do i look? im totally lost at this point? im kinda new to auto repair i know a little but please use terms that a beginner will understand. thanks

steve

 

vacuum line to the vacuum ball behind bumper on pass side runs by the battery to the firewall by the blower motor or the line going from the ball to the motor for its supply

 

ok. so i found the vacuum ball and all the lines going ion and out are fine. i also checked all the other vacuum lines i could find. i have noticed a hissing noise that sounds like it is coming from behind my glove box when i tried to investigate it i learned that the glove box is rivited on and i dont want to break those off. short of pulling the whole dash out is there any way to get back there? could that even be the problem? i dont want to tear the dash out chacing goose eggs ya know?

 

That could definitely be the problem. I had an old vacuum line on a Bronco go bad behind the dash and the hissing drove me nuts. It became all I could here when in the car. Luckily I was able to get to it by simply removing the hvac controls. I would try that if you think you can handle it. Should take just a phillips if remember correctly. You could also try getting on the passenger side floor facing up with a bright flashlight, if you haven't already.