NCBobD

I've been gaining some ground on the heater situation in my 2000 XJ but I've run into one I have seen mentioned in the forums. I'll start with what I've dealt with so far. I replaced the fan resistor... fan problem solved. The jeep was apparently hit in the front right quarter at some point and was rebuilt from there. I discovered it was missing the vacuum ball, which I replaced this morning. While I'm now getting a bit of air out to the feet now, it will not switch to the dash vents at all and the air coming out at the feet is somewhat limited. What else do I need to look at here?

Thanks.

wahoo

There is a vacuum block behind the glove box, you don't have to remove the glove box the door will drop down past where it stops. Hope this helps.

freegdr

Did ya connect to vacuum line to firewall ?

CCKen

You may want to read through this thread:

https://www.cherokeeforum.com/f2/common-183554/

NCBobD

The line was in place and plugged off.

freegdr

x2

NCBobD

Interesting read. Definitely gives me some things to look at. FWIW the cruise control worked fine without the reservoir/plugged off line. I haven't taken it for a drive since adding the reservoir. I'll do that here in a few minutes.

Thanks.

freegdr

So its connected at firewall ?

NCBobD

Yes the line is plugged into the firewall. Location of some things on the 2000 seem to be a bit different than in the linked thread provided. For example, the heater resistor is below the glove box, not behind it. The air door actuator seems to be doing little or nothing. If I pull on the arm leading up to the doors I can manually change airflow. I get a hint of airflow change when I change the switch position. For example, I can get all defrost or a blend of defrost and feet... though not a strong flow to the feet. Switch position change does nothing for mid-level vents

Thanks for the help. Still digging and scratching my head a bit.

CCKen

What door actuator?

What arm? What doors?

Kind of a confusing description...

NCBobD

A search for: "ACTUATOR. Defroster. Vacuum. . Defrost, Defrost Door, Defrost Door Actuator, Defroster Door. 2000 jeep cherokee" brings up what appears to be the piece I'm speaking of. It's just below the glove box next to the heater resistor in my 2000 xj.

CCKen

That's the Recirculaion Air door actuator mate, not the defrost door actuator. Right church, wrong pew.

CCKen

This IS the view you would see if you would saw the complete right side of the dash off and remove the kick panel off the blower resistor block area.

What you would see through the glove box opening is the Recirc door, not the blower resistor block.



I think you need to regroup and list the exact problem(s) you are experiencing, instead of chasing odds and ends.

NCBobD

Ok, lets start again with the problems.

Air direction switch (ADS) in feet only - some air at feet, mostly out of defrost

ADS in mid-level vents only - air from defrost only.

ADS in feet/mid-level position - some air at feet, mostly out of defroster

ADS in feet/defrost position - some air at feet, mostly out of defroster

ADS in defrost only position - air out of defroster vents only

These results occur at idle and while driving down the road.

Repairs made so far: New blower motor resistor which solved the blows on 4 only issue as expected.

Installed missing vacuum ball canister.

Lines under the hood have been inspected from canister to firewall.

CCKen

Attached is a vacuum circuit diagram that shows the various available settings of the mode selector and the vacuum routing to the various actuators that correspond to the mode selector setting. You list five settings and there are seven available. If you look at the defrost door vacuum you will see that in derost setting (5) that all vacuum is vented from the actuator, running the defrost door open, and in the Mix setting (6) the defrost door actuator is run to the mid position, along with the floor door open.

It would appear that, because you do get some door activity at Feet (7), there is vacuum available at the mode selector, but that the defrost door is open all the time. The door actuator may be inop, the door crank arm is broken, or the vacuum lines to the actuator are disconnected. This is what a broken defrost door crank arm looks like:



You might try the Max Air/Recirc selection (11) and see if the recirc door opens & closes. If it does then the mode selector is being supplied vacuum.



Actuators:



You may want to check to see if the vacuum tubing disconnect is secure, as viewed throught the glove box opening. Pic.



To access the defrost door and panel door and their actuators/tubing, you have to remove a bunch of components from the dash. Center Bezel, Radio, Instrument Cluster Bezel, Instrument Panel Top Cover, and Defrost Duct/Demister Adapter.

You should refer to the FSM for instructions pertaining to R&R of these components.

If you do find out that the defrost door crank arm is broken you'll need to figure out how to fix it. I don't know. I've searched using Google and nothing showed up.