Ok...I've done a search and found no definitive answer on this. I only get heat coming from the defrost vents. Anything else blows a tiny tiny bit, just barely.

What I know:
1. blower motor, relay and resistor are working well.
2. A/C unit is working
3. Blend doors and circulation doors are working well
4. Vacuum seems to be working except for one line that is without vacuum. One vacuum hookup on my intake is plugged with what looks like a factory installed rubber cap.

What I don't know:
1. Where the hell are the vent doors that control the other vents? Or what can I do to fix this?
2. Did someone else cap that hole on the intake and that's all I need to repair to fix this?

Thank you all for your help...this is truly an annoying problem...

 

Maybe check the Jeep egg in the front bumper,its a small plastic ball that controls the way your vents open close etc,it might have a hole in one of the lines or cracked maybe.Its a vacuum canister

 

the mystery ball stores vacuum for the vent opening process

 

Forgot to say, I checked the ball too, no sign of leakage, though its hard to hear with the engine running. Which also reminds me, It seems to hold enough vacuum to operate my cruise control, and those are supposed to be related right? Tomorrow I'll check it with soapy water. Any other ideas? lol Also, if it was a vacuum issue wouldnt my other vents not work? IE blend/circulation doors?

 

did you follom the line up to where it goes into the fire wall near the blower motor if i recall r4ight under the dash therir are more vacuum line that go to the vent doors from the dash control

 

Yeah, everything on that line seems to have good vacuum. We're talking about the line that clips onto the firewall, right? Because there is a rubber line that goes through the firewall just 4-5 inches away from the blower motor, that doesn't seem to get vacuum but I can't trace where the line heads to because it gets wrapped up in some stupid wire bundle. I'll have pics later tomorrow. I gotta get to class now.

 

its either gray or white apply vacuum to tha i know one does not connect to any thing its like a vent or some thind

 

The evaporator or heater core may be clogged with dirt, cat hair, leafs, or any other kind of crap, blocking the air flow through the system.

 

it blows out floor only

 

you will be looking for this stuff under dash by pass feet it closes and opens the doors

 

Alright, at this point I have it narrowed down to a (leaky) actuator (or broken tabs holding the actuator arm onto the vent door.) OR not enough vacuum pressure(but this is unlikely because the vacuum has enough pressure to open all the other vent doors.

Diagram is:
Defrost actuator full: yellow

Floor actuator: brown

defrost actuator mid: blue

Vacuum Supply: Black (This is the main line coming in, it *feels* like it has good PSI, it's supposed to be carrying 6-8PSI and I have yet to test for that

Panel actuator: red (THIS is where my problem lies, this actuates dash level vents, somewhere between the switch and the vent door itself something isn't working fully.

Recirculation actuator: green


I used a little piece of wire insulation to jump the vacuum lines together, It easily had enough vacuum to pull the recirc act. so my testing method holds vacuum well. I jumped black(vacuum resevoir) to red (panel actuator) and can hear an actuator start to move. It seems to open the vent door slightly because I get some air coming out. I suppose it's quite likely that my actuator arm is loose or the actuator is leaking?

 

Ok, another update, manually actuated everything (by sucking on each vacuum line lol) panel actuator(red) is the only one that I can't full actuate. So...my problem lies somewhere between the start of the red vacuum line and the vent door itself.

Possible issues: Vacuum leak in the line, vacuum leak in the actuator, actuator arm broken/loose, Vent door prevented opening by debris....Looks like I may have to tear apart the whole damn dashboard and take this **** apart. Anyone have any suggestions?

 

No one has any ideas? lol

 

Bought a vacuum tester today... the incoming vac line is running at 16mm Hg (like 7.95PSI) so it's working perfectly fine. The actuator doesn't have a vacuum leak either. It has to be the door blocked by debris or the actuator arm is broken. I need a write-up on removing the dash of a 97+ it really sucks that I have to take this all out.