HVAC vacuum lines

[Camdenst]

Hey guys... I have a vacuum issue. It’s an 05 LJ and I’m only getting air/ heat through the top vents. The defroster and foot wells are out. I’ve already replaced the line inside the engine bay and tried swapping the control panel. Looking at the lines through the glove box they look good. Any ideas on how to trouble shoot the leak or does it require professional tools at this point?

 

[WWII Jeeper]

Did you make sure the two one-way check valves were facing the proper direction . These are little round valves similar to a garden drip line valve, and they would be under the hood, one near the manifold towards the firewall, the other near the heater core inlets. Location could vary depending on any previous owner alterations.

I went thru days of frustration, a new dash control panel, only to find I reversed the valves while checking my vac lines......
Sorry for the repost edit: My TJ is a stock 06, 4.0, 6 spd manual

 

[Camdenst]

I’ll Look into it. It didn’t even cross my mind because the replacement came assembled with pre bends.

 

[WWII Jeeper]

I’ll Look into it. It didn’t even cross my mind because the replacement came assembled with pre bends.

Didn't cross mine either. I checked them for clogs, and when I couldn't blow air thru it, I considered tossing and going new.........then the brain came out of my butt, and I tried the other side.......what a concept...

 

[T Crawford]

Could be one of the stepper motors that move the blend does stopped working the late years moved away from vacuum actuators. See if you can see them under the dash and watch them

 

[Camdenst]

Swapped the direct of the valve coming off the intake... nothing. I’ll look at the stepper motors this weekend. Total “Jeep” issue... something so simple and so frustrating.

 

[Camdenst]

Here is where I stand and what I’ve learned. I have replaced the vacuum line inside the engine bay, tried a new control panel and inspected every line I could see all without resolve. I was able to manually turn the vents from under the dash from all front to defrost/ foot well. My question is... is this still a vacuum leak or did both actuators fail and if it is a leak how to find out where the leak is?

 

[T Crawford]

The stepper motors come off pretty easy. I have you looked at factory service manual for diagnosis tree?

 

[Camdenst]

Would the whole dash need to come out to get the stepper motors, they seem very well tucked up in the dash

 

[Camdenst]

An update for you guys. It was actually the part on the back of the hvac control unit, behind the knob where the lines plug in. Unfortunately they do not make the part any longer so you have to buy a new hvac control panel.