TJ "air" stuck in defrost setting??

[RICK]

I had the defrost on this morning.
At lunch I turned the switch to "bi-level air" and the cold air came out of the defroster vents only.
That is the only position that works on the "air direction" switch.
A/C and fan work properly, but the only place air comes out is the defrost vents, regardless of the switch position.
Is this something I can fix at home in under 20 minutes, or should I take to the dealer tomorrow morning?
It is still under the extended service contract, but just damn inconvenient to leave at the dealer all day for a simple 15 minute fix (if it is).

[GreaseMonkey]

Look at all the thin plastic vacuum lines near the firewall. I guarantee you have one disconnected, ripped, torn, or with a hole in it.

[RICK]

Thanks, is this plastic tube behind the center bezel or behind the glove box area?

[GreaseMonkey]

My bad...under the hood near the firewall. If it's a 4.0L look on the right side of the engine bay first.

[FrankNBrew]

The vacuum line connects on the side of the intake manifold, right below where the large vacuum line plugs in from the PCV valve. On mine the vacuum connection is swelled from the oil from the PCV system. It falls off if I hit it when under the hood. I need to replace the rubber end. You might have the same thing.

[RICK]

Found it..but it looks good. all connections are tight, and no cracks or anything noticably wrong..right to the point it goes into the firewall.

[Jeeperz Creeperz]

When you have a vacuum leak in the climate control system the system will default to defrost so that you can drive the vehicle. Doesn't happen too often in the summer, but in the winter your windshield will fog up - it's a safety thing.

Check for vacuum leaks at all the connections.

Also, pull the switch off and see if the back side is cracked.

[RICK]

Thanks everyone..but apparently it's not a 15 minute simple fix.
I'll let the dealer do it tomorrow.

[Tonka]

Originally Posted by RICK

Thanks everyone..but apparently it's not a 15 minute simple fix.
I'll let the dealer do it tomorrow.

I'm willing to bet that your problem is one of 3 plastic arms is broken. They are attached to the vent flaps, and to the vacuum actuators on the drivers side, middle of the heater duct assembly.

I have had to replace 2 of mine.

It is a 5 minute simple fix, and that's taking the non-contortionist method of removing the knee panels under the steering column.
I drew some red arrows, pointing to the pieces that break(you usually cant see the break till you pull the part)

EDIT: after being under Rick's dash, D.C. at some point replaced the problematic HVAC stuff with a smaller, upgraded version My diagram applies to 97 and 98 for sure.

[RICK]

Thanks Eric.
You have a PM.

[GreaseMonkey]

So is it fixed?

[victorymike]

Yeah...is it fixed? Inquiring minds want to know.

[Tonka]

I'm calling him now to set up a time to look at it.

[Rocky]

My guess is the mode selector is bad.

[Big Daddy Rubicon]

Blinker fuild is low, had it before. Don't forget to check the lines behind the glove box. I have seen things from the glove box (books, tools, stuff) hit the lines and cause problems.

[RICK]

Well, I checked all the cheapo plastic vaccum lines and all the fittings.
I must have jiggled the right connection somewhere.
It worked fine yesterday.
Sometimes I'm amazed at my pneumatic and mechanical skills *luck*.
Tonka is coming over tomorrow to check my work:miff:

[Jeeperz Creeperz]

Does anybody have a part number for the defrost door arm?

I called the dealership today and apparently it's been superceded to the entire plenum assembly....

[OlllllllO]

THANKS TONKA!!! I had the same problem and after removing the panel from under the steering wheel I found that one of the arms in the diagram was broken. I am going to the dealer today for a part, Ill get a number if I can.

[Lothos]

weird, my only issue is in "floor" mode I am also getting air out the drefrost vents.

[OlllllllO]

Here is what I found out.

There are two D.C. part numbers 05014108AA, and 04886086AB. Unfortunately D.C. has decided to discontinue selling these parts in favor of a $200 vent assembly.

luckily Omix Ada was smart enough to pick up where D.C. left off and sells these parts.

The Omix Ada part numbers are 17910.01 (replaces 4886086AB) and, 17910.02 (replaces 5014108AA).

These parts run between $13-20 each and are pretty easy to install.

I found the great information about this here: http://www.jeepforum.com/forum/showthread.php?t=66176