[doubleup]

I posted this problem a few days ago, however was told to search the topic. I've searched relentlessly on here and can't find someone who has had a similar problem. I pulled the unit out and messed with some of the wires connections to see if they had come loose, but they all seemed fine. All speeds work; Will only blow on feet only or defrost/feet combo.

Anyone know where to go from here?

[CDNjeepgrl]

exact same problem.. been that way since i bought the jeep last january tho
so any help would be appreciated here as well....

[Rocky529]

You have a vacuum leak somewhere and it isn't opening and closing the evaporator case doors.

[CDNjeepgrl]

even with the '97?
i could be very wrong, and am probably going to sound pretty stupid, so don't haze me guys, lol... but i thought having the slider function, and the earlier tj's there was a difference.... no?

[doubleup]

Vacuum leak, wonderful. I'll look around and see what I can find. I've looked around the block for vacuum leaks and have been unsuccessful thus far.

[Rocky529]

Originally Posted by ~eMM~

even with the '97?
i could be very wrong, and am probably going to sound pretty stupid, so don't haze me guys, lol... but i thought having the slider function, and the earlier tj's there was a difference.... no?

I think only the hot/cold function works on a slider, and the location selector is a vacuum.

[DUGA BOY]

not to be a bringer of bad news but mine is the same way. the control arm connected to the flap that opens the vent broke on mine and the dealership wants $1,400 to repair it. STUPID PLASTIC!! look under the driverside dash and you will find the three canisters opperated by vacume to open the flaps for your hvac unit. if one is disconected or broke thers the problem also look at the vacume lines if one is loose that might b your problem

[Wheelin98TJ]

Yup, definitely sounds like a vacuum leak.

I've never encountered this problem, so I can't offer much help.

Here's some info from the FSM:

VACUUM SYSTEM
Vacuum control is used to operate the mode doors
in the heater-A/C housing. Testing of the heater-A/C
mode control switch operation will determine if the
vacuum, and mechanical controls are functioning.
However, it is possible that a vacuum control system
that operates perfectly at engine idle (high engine
vacuum) may not function properly at high engine
speeds or loads (low engine vacuum). This can be
caused by leaks in the vacuum system, or a faulty
vacuum check valve.
A vacuum system test will help to identify the
source of poor vacuum system performance or vacuum
system leaks. Before starting this test, stop the
engine and make certain that the problem isn’t a disconnected
vacuum supply tube at the engine intake
manifold vacuum tap or the vacuum reservoir.
Use an adjustable vacuum test set (Special Tool
C-3707) and a suitable vacuum pump to test the
heater-A/C vacuum control system. With a finger
placed over the end of the vacuum test hose probe
(Fig. 8), adjust the bleed valve on the test set gauge
to obtain a vacuum of exactly 27 kPa (8 in. Hg.).
Release and block the end of the probe several times
to verify that the vacuum reading returns to the
exact 27 kPa (8 in. Hg.) setting. Otherwise, a false
reading will be obtained during testing.

VACUUM CHECK VALVE
(1) Remove the vacuum check valve. The valve is
located in the (black) vacuum supply tube at the
intake manifold vacuum tap.
(2) Connect the test set vacuum supply hose to the
heater (natural color) side of the valve. When connected
to this side of the check valve, no vacuum
should pass and the test set gauge should return to
the 27 kPa (8 in. Hg.) setting. If OK, go to Step 3. If
not OK, replace the faulty valve.
(3) Connect the test set vacuum supply hose to the
engine vacuum (black color) side of the valve. When
connected to this side of the check valve, vacuum
should flow through the valve without restriction. If
not OK, replace the faulty valve.

HEATER-A/C CONTROLS
(1) Connect the test set vacuum probe to the heater-
A/C vacuum supply (black) tube in the engine
compartment. Position the test set gauge so that it
can be viewed from the passenger compartment.
(2) Place the heater-A/C mode control switch knob in
each mode position, one position at a time, and pause
after each selection. The test set gauge should return to
the 27 kPa (8 in. Hg.) setting shortly after each selection
is made. If not OK, a component or vacuum line in
the vacuum circuit of the selected mode has a leak. See
the procedure in Locating Vacuum Leaks.

LOCATING VACUUM LEAKS
(1) Disconnect the vacuum harness connector near
the back of the heater-A/C mode control switch on
the control panel.
(2) Connect the test set vacuum hose probe to each
port in the vacuum harness connector, one at a time,
and pause after each connection (Fig. 9). The test set
gauge should return to the 27 kPa (8 in. Hg.) setting
shortly after each connection is made. If OK, replace the
faulty mode control switch. If not OK, go to Step 3.
(3) Determine the vacuum line color of the vacuum
circuit that is leaking. To determine the vacuum line
colors, refer to the Vacuum Circuits chart (Fig. 10) or
(Fig. 11).
(4) Disconnect and plug the vacuum line from the
component (fitting, actuator, valve, switch, or reservoir)
on the other end of the leaking circuit. Instrument
panel disassembly or removal may be necessary
to gain access to some components.
(5) Connect the test set hose or probe to the open
end of the leaking circuit. The test set gauge should
return to the 27 kPa (8 in. Hg.) setting shortly after
each connection is made. If OK, replace the faulty
disconnected component. If not OK, go to Step 6.
(6) To locate a leak in a vacuum line, leave one
end of the line plugged and connect the test set hose
or probe to the other end. Run your fingers slowly
along the line while watching the test set gauge. The
vacuum reading will fluctuate when your fingers contact
the source of the leak. To repair the vacuum
line, cut out the leaking section of the line. Then,
insert the loose ends of the line into a suitable length
of 3 millimeter (1/8-inch) inside diameter rubber
hose.

[doubleup]

Awesome diagrams. You know if a regular vacuum gauge will work?

[rmack]

duga boy wholesale mopar has the arms for the flappler for the heater box.

[kcphilaflyer]

yup, same thing happened to me the other week, vacuum......score one for the warranty!!!!!!!

Also while it was in, the said the rear pinion seal was leaking and replaced it.....

total cost = $0

take advantage of it while i can i guess

[The Mean Fish]

I had the same problem on mine (100% my fault) but I could hear the leak under the hood and finally found it.

[xulcuz]

Originally Posted by DUGA BOY

not to be a bringer of bad news but mine is the same way. the control arm connected to the flap that opens the vent broke on mine and the dealership wants $1,400 to repair it. STUPID PLASTIC!! look under the driverside dash and you will find the three canisters opperated by vacume to open the flaps for your hvac unit. if one is disconected or broke thers the problem also look at the vacume lines if one is loose that might b your problem

I was just reading about this at barnes and nobel about 30 min. ago. I cant remember what magizine it was, maybe JP mag. Im not sure but thats what they said that the dealer wanted $1400 to fix it but that they came up with a way to rig it for liek $2.00. So check your news stand for the mag I guess. Hope that helped a little.

[gdl]

Here's a thread with lots of good info. Skip down to post #14, there's some good troubleshooting info.

http://www.jeepforum.com/forum/f9/air-vent-problems-66176/

And $1,400 is absolutely ridiculous to fix the broken control arms. You can buy them at http://www.discountjeepparts.com/index.php/cPath/408_412 for $13.95 each. They're the last two items on that page. Installing them is a bit of a pain but when I did mine, I'd guess it was no more than two or three hours of labor.

[xulcuz]

Just checked and it is JP mag in there newest issue they have a write up on how to fix it for like $2.50!