Replacing HVAC vacuum lines behind the dash

[JayOh]

Hello from Australia, where we all drive on the wrong side of the road while sitting in the passenger seat!
(Just my way of saying we are RHD )

I picked up a nice looking 2003 model recently, but turns out beauty is only skin deep and it has issues. One issue is the ventilation only blows on to the windscreen - my mechanic did a smoke test and found the HVAC vacuum lines under the dash appear to have been chewed on by vermin. I need to replace the vacuum lines but don't know where to source replacements or what is involved in getting access to do the work.

Is this a whole dash out situation or can you get access by removing the glove box and the dash centre?

Where can I source replacement lines?

Thanks in advance!

 

[Chris]

You're going to need to pull the dash most likely.

Since they're just vacuum lines you can get them at any auto part store.

 

[JayOh]

You're going to need to pull the dash most likely.

Since they're just vacuum lines you can get them at any auto part store.

Thanks Chris

 

[NavOhio]

Hello folks, I only had air out of the defrost and feet. Due to this forum I learned how the HVAC system worked and discovered the engine vacuum line on the driver side of the engine came off. There is a picture of the vacuum system in the TJ Service Manual. I hooked it back up and everything works as it should per the HVAC knobs on the dash. I now get air out of the dash vents on that setting. Thanks everyone.

 

[hear]

Before I tore apart the dash, I would make double certain the lines from the intake over to the firewall & vacuum reservoir were in good shape & connected, as well as the 2 check valves. I've had them crumble to the touch on every TJ I've owned.

 

[cpwolf]

He did say that they smoke tested and must have seen smoke behind the dash, but these are good check points.

I pulled all this, and if you pull all the center stereo section, the glove box etc, you may see what you need. May still need to do the dash pull, but if you can run smoke it in and see a leak, maybe you get lucky.

 

[JayOh]

The mechanic pointed out where they found the leak, this is behind the glovebox (remember it's RHD) in the first pic you can see the hoses coming from the control panel appear to be ok, but the hoses heading back are chewed - the brown one is definitely missing an inch or so but it's hard to tell if any other hose is damaged. But I can't see any easy way of getting back there without removing the dash.

 

[TJ Kamstruct]

Hey jayoh- I’m just wondering if you completed this task. I’m having the same. There’s a leak in two of my vent selector lines but I haven’t figured out how to pull and replace them yet without removing the whole dash

 

[Chris]

Pull the dash, my guess is that'll be easier and you can replace anything else you find that needs replacing back there at the same time.

 

[Rancho LJ]

Here are a couple of photos showing how the actuator vacuum lines are routed on an 05 LJ. Your HVAC box made different depending on the year. If nothing else, it will give you an idea of what to look for under your dash.

There are two actuators that are accessible from the driver's side footwell under the dash, and one actuator visible from the glove box for the recirculation door. The lines are routed behind a HVAC support bracket behind the glove box. If you remove the screws on the fuse block and move it out of the way, you should be able to feed the vacuum line harness out after disconnecting the the lines from the actuators.

 

[AndyG]

Thanks for posting this.

Andy

 

[JayOh]

Hey jayoh- I’m just wondering if you completed this task. I’m having the same. There’s a leak in two of my vent selector lines but I haven’t figured out how to pull and replace them yet without removing the whole dash

no, not yet - I've been waiting for the mechanic to have the time and space to do it. I have just moved house and now have space to work on the jeep so I may have a go at this over the holiday break.

 

[JayOh]

Here are a couple of photos showing how the actuator vacuum lines are routed on an 05 LJ. Your HVAC box made different depending on the year. If nothing else, it will give you an idea of what to look for under your dash.

There are two actuators that are accessible from the driver's side footwell under the dash, and one actuator visible from the glove box for the recirculation door. The lines are routed behind a HVAC support bracket behind the glove box. If you remove the screws on the fuse block and move it out of the way, you should be able to feed the vacuum line harness out after disconnecting the the lines from the actuators.

View attachment 660042

View attachment 660043

Thank you - very helpful pics!