Hey all I just bought a 1999 Jeep Cherokee classic and I started having problems with my heater. The heat blows hot but it only comes out of the defrost vents and wont blow out anywhere else.

From what I read could it be the vacuum lines? or could it be something else? If anyone could shed some light on this problem it would be greatly appreciated!

Thanks,
Brian

 

check the vacum line from the vacuum balll behind the front bumper pass side they run from the blower motor area to the bumper comon break point near batt

 

I have the same problem with my 91 laredo. But I have checked every single vacuum line I can find and they are all fine. I've even taken the dash controls out and the vacuum lines are good there too. Is there something else I could be missing?

Also what does that vacuum ball in the bumper do?

 

have you checked to see if its getting vacuum to the ball ,it stores vacuum so the door will stay open when ac is on so the ac come out the dash vent and so forth

 

Ok so I just checked the vac lines going to the ball. No vac, so I traced the line to the intake and found the fitting in the intake clogged with oily junk. I cleaned that, but found the small vac Regulator looking thing above that, and distributing block on the pass side all clogged with DIRT! I cleaned the dirt out and then the heater and AC started working properly.

But now Im worried about how the vac line got dirt in it. Does that mean my air filter is letting all that dirt into my intake and into my vac lines and worse my engine?