Blend doors not working - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Cherokee & Comanche Forums > XJ Cherokee Technical Forum > Blend doors not working

Jeep Gear & Install Packages!Rough Country Lift Kits and Parts!USA Standard Chromoly Front Axle Shaft Kits with Dana 30 4

Reply
Unread 08-08-2012, 12:36 PM   #1
spalatucc
Registered User
1997 XJ Cherokee 
 
Join Date: Jun 2012
Location: Vienna, Virginia
Posts: 15
Blend doors not working

I just replaced my heater core, evaporator core and blower motor and before this the air would flow through all my vents fine. Now it seems the blend doors are not opening when I try to turn the air on. I made sure I reattached all the vacuum hoses in their correct positions before putting the HVAC back in as well. Any ideas why as to why it isn't working correctly now?

spalatucc is offline   Reply With Quote Quick reply to this message
Unread 08-08-2012, 05:02 PM   #2
AZ Jeff
Web Wheeler
2014 JK Wrangler 
 
Join Date: Sep 2005
Location: San Tan Valley Arizona, AZ
Posts: 7,452
Since all the doors are vacuum operated, and you say none of them function (the are called "MODE" doors, BTW. The "BLEND" door controls air temperature), I would guess you have no vacuum going to your mode control knob. Check that first.
__________________
AZ-Jeff
1992 XJ -- stock (RIP)
2000 XJ -- lots of basic mods. Sold to fellow forum member. I miss it.
2014 JK -- the project is just starting!
AZ Jeff is offline   Reply With Quote Quick reply to this message
Unread 08-08-2012, 07:15 PM   #3
ThaKmFb
Registered User
 
Join Date: Jul 2011
Location: Richmond, Virginia
Posts: 37
The blend door is actually cable driven. The mode doors are vacuum operated. Make sure you have a black and a gray hose goin through the firewall with the evaporator connections. The black one is the supply to the control head the gray one goes to the heater control valve. Make sure you dont have the switched. If those are o.k. check and make sure you have vacuum at the a/c control head. Then go from there.
ThaKmFb is offline   Reply With Quote Quick reply to this message
Unread 08-10-2012, 04:50 PM   #4
spalatucc
Registered User
1997 XJ Cherokee 
 
Join Date: Jun 2012
Location: Vienna, Virginia
Posts: 15
Mode door

Thanks guys for the replies. When I cycle to a different mode the doors don't open, but if I cycled all the way through and on the way back stop at the one I want it opens correctly. I made sure I plugged all the vacuum hoses up correctly (I've made the mistake of not taking pictures and documenting where things go when I rebuilt my engine). Also, I didn't even touch the one on the control knob
spalatucc is offline   Reply With Quote Quick reply to this message
Unread 08-10-2012, 06:17 PM   #5
AZ Jeff
Web Wheeler
2014 JK Wrangler 
 
Join Date: Sep 2005
Location: San Tan Valley Arizona, AZ
Posts: 7,452
Quote:
Originally Posted by spalatucc View Post
Thanks guys for the replies. When I cycle to a different mode the doors don't open, but if I cycled all the way through and on the way back stop at the one I want it opens correctly. I made sure I plugged all the vacuum hoses up correctly (I've made the mistake of not taking pictures and documenting where things go when I rebuilt my engine). Also, I didn't even touch the one on the control knob
That sorta sounds like a control problem. Check the vacuum lines that run from the control panel to the junction block behind the glove compartment on the heater box.
__________________
AZ-Jeff
1992 XJ -- stock (RIP)
2000 XJ -- lots of basic mods. Sold to fellow forum member. I miss it.
2014 JK -- the project is just starting!
AZ Jeff is offline   Reply With Quote Quick reply to this message
Unread 08-10-2012, 06:28 PM   #6
ThaKmFb
Registered User
 
Join Date: Jul 2011
Location: Richmond, Virginia
Posts: 37
Sounds like maybe the control head
ThaKmFb is offline   Reply With Quote Quick reply to this message
Reply

Tags
a/c , blower motor

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.