Heating/AC blend air mixture location

[swhiting]

I got a 99 GC with heat blowin out the driver side vents and AC blowing out the passenger side vents. I suspect the air blend door is stoke/broke or the servo is bad. Anyone know about this? Like where they are located and how to get to them? Have others had this problem?

[Junoir]

I have exactly the same problem, 99 JGC with climate control dual zone control. I had ask for help in other forum but no help found. Please anyone HELP!!!!

I think it's more like a trap ventilation problem, you know... the thing that do the mixture of fresh air with hot air to set the temprature. Look's like it got stuck open!

The thing is I don't have a clue where it is exactly.

[swhiting]

Dispite not knowing where I was to look I at least knew what I was looking for. So I spent approx 4 hours carefully ripping the dash out to find the passenger side air blend valve. As a side note, the driver side air blend servo is simple to find. It's right behind/under the glovebox and if it takes you longer than 5 minutes to rip out, you've done something wrong. Anyway, I think I have narrowed down the pass. side valve; however, I have not yet spotted it. It is in the most difficult location possible: center dash, behind the inner dashboard structure. Behind the console, under the dash cap, behind the "inner dash". It is not rocket science getting to but it is a lot of work.

Of course, this is still all hunches as I havent got the POS in my hand yet. I'll keep ya posted. I would still appreciate advice if anyone has any.

Cheers!

[swhiting]

ok, I found it, it was right where I thought it was. However, I still can't get at it. Its between the heating duct assembly and the firewall. It looks like I may have to pull the heater and AC lines in order to pull the assembly out enought to work on it...pretty much worst case senerio. Good news is it is all busy work, LOTS of it. Haven't even really got my hands dirty.

Has anyone else pulled heating assemblies or heating cores or AC condensers out of 99+ GCs? Just wondering if there is an easier way to get at this passenger blend air door assembly.

Cheers.

[Junoir]

I'm thinking, is it possible that it is only a bad electrical connection somewhere in there, jeep seem to have theses kind of problem. The cervo valve side has a bad connection or the climate control side.

I had it fix a while a go, while it was still under waranty, the dealer replace my module with another vehicules and it work for 5 month.
It was on the driver side when it first happen, now it on the passenger side. The werd thing is that when they had the module(my original) tested it was responding correctly.

Is there any way to test the electrical connection or test the cervo valve with a multimeter.

I do wish you good luck, because I'm also waiting for the solution.

[jon7]

[quote=swhiting]Dispite not knowing where I was to look I at least knew what I was looking for. So I spent approx 4 hours carefully ripping the dash out to find the passenger side air blend valve. As a side note, the driver side air blend servo is simple to find. It's right behind/under the glovebox and if it takes you longer than 5 minutes to rip out, you've done something wrong. Anyway, I think I have narrowed down the pass. side valve; however, I have not yet spotted it. It is in the most difficult location possible: center dash, behind the inner dashboard structure. Behind the console, under the dash cap, behind the "inner dash". It is not rocket science getting to but it is a lot of work.

Of course, this is still all hunches as I havent got the POS in my hand yet. I'll keep ya posted. I would still appreciate advice if anyone has any.

Cheers![/QUOTE

[jon7]

[quote=swhiting]Dispite not knowing where I was to look I at least knew what I was looking for. So I spent approx 4 hours carefully ripping the dash out to find the passenger side air blend valve. As a side note, the driver side air blend servo is simple to find. It's right behind/under the glovebox and if it takes you longer than 5 minutes to rip out, you've done something wrong. Anyway, I think I have narrowed down the pass. side valve; however, I have not yet spotted it. It is in the most difficult location possible: center dash, behind the inner dashboard structure. Behind the console, under the dash cap, behind the "inner dash". It is not rocket science getting to but it is a lot of work.

Of course, this is still all hunches as I havent got the POS in my hand yet. I'll keep ya posted. I would still appreciate advice if anyone has any.

Cheers![/QUOTE yes

[jon7]

yes I have the same proplem, my drivers side only blows cold air....the passenger side is fine....i paid my mechanic 500 to fix it and it only worked for a week....He wants to repair it again, said that he ordered 3 new parts from the jeep dealer...Is he taking me to the cleaners???? Also my heated seats stopped working the passenger then the drivers.... any advice appreciated

[swhiting]

Jon7, you are getting taken if it was just the servo he replaced....That only takes a few minutes to replace and costs less than 100. If, however, it was some part of the door mechanism, then that cost is justified as you have to tear into the ducking housing to get at the components, which (as I am learning currently) is about the nastiest thing there is to do on the inside of a cherokee, at least the late models.

[jon7]

Originally Posted by swhiting

Jon7, you are getting taken if it was just the servo he replaced....That only takes a few minutes to replace and costs less than 100. If, however, it was some part of the door mechanism, then that cost is justified as you have to tear into the ducking housing to get at the components, which (as I am learning currently) is about the nastiest thing there is to do on the inside of a cherokee, at least the late models.

swhiting yes my machanic did you alot of work to my jeep...I did try fixing the part under the glove box but could not snapout the glove box ...How does this come off ?????? Also Do u know any thing about heated seats? Thank You Jon7

[Junoir]

swhiting,
How did you get to the door mechanism? My problem seem's similar, it stop working the first time after something crack or broke.
Do you think that a air filter(add-on) for the jeep would help to avoid this problem again?

[skuhler]

It looks like the problem continues thru the 2002 models. My dealer has had several customers with the problem, including mine, and has a service bulletin from Jan 04 with instructions. Since it has been a few months since this thread was active, any updates on the blend mechanism and whether this fixed your problem? Any hints on getting to the mech quicker and easier? Sounds like some people had servos replaced and it worked only a short time, any updates?

[swhiting]

This post is an update on my previous messages regarding this subject. My problem was indeed the passenger side air blend valve. To get to it is about as bad as trying to get to a cylinder ring. Luckily, its all clean, pretty much simple work, nothing technical. I carefully tore my dash apart, starting from the glovebox, then the center console, then the cap, then the dash frame, then the NASTY inner dash frame, and finally I completely removed the entire ducting assembly in one piece. This requires discharging the ac and draining the coolant. After this is done you will be staring at nothing but the sound-proofed side of your firewall...kinda spooky. None of the work is hard and I didn't use a manual.
Once the ducting assembly was removed from the interior, it pretty much has a top and bottom half. It all comes apart and finally...there was the problem. Some tiny stupid freakin' piece of plastic broke off the shaft that connects the servo with the door. Well, it rendered the whole assemblu useless. Even thought only one piece was broke, I replaced the servo, door, and connecting shaft. Then it all goes back together the way it came apart.
So, in summary, it requires about 20-25 hours labor if you dont know what you are doing *raises hand* and maybe 10 hours if you have previous experience with this level of tear-down. Really though, there is nothing technical about it. Just keep you parts VERY organized because you well have hundreds of fasteners removed and I guarentee you wont know which ones go where when you get'er back together. As it was, I had about seven leftover fasteners and I triple check everything throughout the re-assembly.
I hope this helps. I wish it woulda been here months ago.
NOTE: if your problem is with the DRIVERS SIDE blend air. It only takes about 10 minutes to get to. Just remove the glovebox and there is the servo. However if the problem is inside the assembly, you will have to completely remove the ducting as described above. There just really isnt a way around this unless you have a way or willing screws out of holes at the back of the ducting assembly.

Good luck!

[kweitzman]

I wish to add my two cents...
This was a very timely thread for me as my 99 GC heat failed on the passenger side. Error codes on the Auto zone control indicated 47, 52, and 54, all of which indicated improper travel of the blend air doors.

I tore it down and found the door hinge of the passenger blend door was broken where the pin went into it. Also, the pin has a stop tab that was broken off. That caused the actuator motor to keep running and put the pressure on the hinge itself, causing it to break. I believe the auto zone control senses the increase in current when the stop tab is engaged, and then tells the actuator to stop. This actually feeds back info to the controller regarding door travel distance so that the controller has a sense of the position of the door. There are only the two wires to each actuator so the increased current reading must act as a feedback to the controller. I also found broken stop tabs on the the driver side air blend door and the recirc air door though they were still functional.

Taking the broken door and three pins to the Jeep dealer, I learned that the blend door is now only sold as a sub-asssembly of both blend doors. Apparently Jeep has recognized the problem. The dealer says he has sold quite a few of these lately. The sub-assembly cost $129.00. That took care of two doors and their associated pins. An additional pin for the recirc door cost another $20.00.

Anyway, the job is done. It took about 20-some hours of labor. Have an AC shop do the evac and recharge. The rest is easy but time consuming. I recommend purchasing a hose-clamp pliers from sears at a cost of about $10.00, or you can get them from the Snap-On guy for about $129.00. You definitely need a clamping pliers because it is a tight reach at the firewall. Everything else is a 10mm and 13mm socket or box wrench and phillips screws. Be sure to disconnect the battery before starting the job and allow it to sit for a few minutes unless you want to risk triggering the airbags. Label the fastener groups (use a muffin pan). I still had about 7 left over fasteners regardless.

A factory manual really helps. I bought one on E-Bay for $50.00. Pulling the dash is scary, but just take it slow. I did it. My wife and son helped. Everything works great now and we saved better than $500.00 in labor and who knows how much in parts markup. With parts, special tools, and AC service the job cost me about $260.00.

Good luck.

[bwwilson]

Thanks to the two persons posting their experience. It was very helpful in determining what course I wanted to take.

I had the same passenger side heater problem in my '99 JGC Limited. After reading this, I decided I didn't have the skills/time to do it myself.

I took it to the dealer and ended up paying about $1000.00 to get it fixed. OUCH!

Now my ABS (and sometimes Brake) warning lights are coming on about every other time I drive it. (particularly in the rain) I'm really getting sick of these little problems.