ZJ climate control

[mbalbritton]

So I can not switch the direction of my HVAC in my ZJ. Turn the knob all you like and all it does is blow straight out. No floors, no defrost.

So I tracked the culprit down to a disconnected vacuum line under the hood. Where the line comes off the manifold and goes to a T junction that goes through the firewall or up to the front of the Jeep for some damn reason that I can’t fathom.

Anyway, it was disconnected from the T junction to the firewall by means of dry rotted plastic tubes. Every time I touched the plastic lines they would just break off more and more. I guess 20 years and 250k miles is more than they can handle.

Anywhoooo, it would seem that my only recourse is to remove the dash and replace the lines. Anyone had any better success than having to go through all that?

Why the hell are these vacuum actuated? Even with as old as this is, there are plenty of electronics on the bastard to go ahead and make this electrical as well, DAMN!

 

[Tim C]

Once you get under the dash it's probably going to be in good shape. It's the underhood heat that makes it brittle. I'd just run some new rubber line under the hood and run it. The part going forward likely goes to a vacuum reservoir so the doors don't change at wot.

Other than rotten vac lines the system is pretty reliable. The new junk with electric motors are a constant headache.

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[a_kelley]

You may can just run a new plastic hose and pick it up at the junction block or run it behind up to the control unit.. lmk if you want vac diagrams.

 

[grapehead]

I had good luck on my xj in a similar situation finding a structurally ok part of the hard plastic line near the firewall and sleeving it with small rubber vac hose, and running that to up the T.