Heat only coming out of defroster vents - 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 Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > Heat only coming out of defroster vents

OPTIC ARMOR WINDOWS all sale now !!!!!!!!Spartan Locker Special Forum Prices Dana 30 44 60 Ford 8.850" LED Light Bar with Overhead Mounting Brackets $69

Reply
Unread 01-23-2009, 02:44 PM   #1
thirteen
Registered User
1996 ZJ 
 
Join Date: Jan 2009
Location: Pennsylvania
Posts: 17
Heat only coming out of defroster vents

Regardless of the setting, heat will only come out of the defroster vent locations, not the dash vents or the lower vents.

Seems the controller that redirects the air must be bad... is it easily accessible? Is there anything in particular I should be looking for or aware of?

thirteen is offline   Reply With Quote
Unread 01-23-2009, 02:50 PM   #2
jetguy81
Registered User
2005 TJ Wrangler 
 
Join Date: Dec 2008
Location: Newport News, Va
Posts: 94
Look under the hood for loose vacum line, that happened to me once. I'm not with my jep at the moment, so I cant be more descriptive but it was very obvious on mine.
__________________
Big VA!
jetguy81 is offline   Reply With Quote
Unread 01-23-2009, 07:41 PM   #3
kmb0427
Registered User
2000 WJ 
 
Join Date: Jan 2009
Location: Birmingham
Posts: 37
does your cruise control work?
kmb0427 is offline   Reply With Quote
Unread 01-24-2009, 07:09 AM   #4
mdav8629
Registered User
1999 WJ 
 
Join Date: Oct 2008
Location: indiana
Posts: 20
limited or laredo. digital display? two different heat setups available. laredo will probably be hard plastic vacuum line if your cruise doesn't work, limited blend doors???
mdav8629 is offline   Reply With Quote
Unread 01-24-2009, 07:36 AM   #5
cmonson
Registered User
 
Join Date: Nov 2006
Location: Columbus
Posts: 1,546
this is NOT blend doors. This is a vacumn line. When you lose vacumn the selection defaults to the defroster setting for safety reasons. Typically I believe they fail by the battery. I would just closely follow each vacumn line and look for a split or tear.
cmonson is offline   Reply With Quote
Unread 01-24-2009, 09:41 AM   #6
thirteen
Registered User
1996 ZJ 
 
Join Date: Jan 2009
Location: Pennsylvania
Posts: 17
Quote:
Originally Posted by kmb0427 View Post
does your cruise control work?
Haven't used it. Is this related to vacuum as well?

And for those that asked it's a Limited (orvis)
thirteen is offline   Reply With Quote
Unread 01-24-2009, 10:44 AM   #7
cmonson
Registered User
 
Join Date: Nov 2006
Location: Columbus
Posts: 1,546
Just do a search for defroster only, and some posts will come up. Look at the fittings by the firewall, and under the battery tray. I am willing to bet this is a vacumn issue and is an easy fix.
cmonson is offline   Reply With Quote
Unread 01-24-2009, 10:55 AM   #8
04WJGuy
Registered User
2004 WJ 
 
Join Date: Apr 2007
Location: Blairmore, Alberta
Posts: 177
Mine did the exact same thing 2 years ago, was a small crack in the vaccum line. Once it was fixed I haven't had any problems since.
04WJGuy is offline   Reply With Quote
Unread 01-24-2009, 12:27 PM   #9
kmb0427
Registered User
2000 WJ 
 
Join Date: Jan 2009
Location: Birmingham
Posts: 37
Quote:
Originally Posted by thirteen View Post
Haven't used it. Is this related to vacuum as well?

And for those that asked it's a Limited (orvis)
Well, I have the same problem with my 2000 and i also have no cruise control and then i got on here a bit and found out that people were having the defrost problem along with no cruise control. My dad and i could find no vacuum leaks either. so he detached the vacuum line from the cruise control module and held it down with his finger and all my vents worked fine. so we're guessing it has to be a leak in the cruise control module. we're gonna look more into this week.
kmb0427 is offline   Reply With Quote
Unread 01-24-2009, 01:14 PM   #10
thirteen
Registered User
1996 ZJ 
 
Join Date: Jan 2009
Location: Pennsylvania
Posts: 17
Quote:
Originally Posted by kmb0427 View Post
Well, I have the same problem with my 2000 and i also have no cruise control and then i got on here a bit and found out that people were having the defrost problem along with no cruise control. My dad and i could find no vacuum leaks either. so he detached the vacuum line from the cruise control module and held it down with his finger and all my vents worked fine. so we're guessing it has to be a leak in the cruise control module. we're gonna look more into this week.
Thanks for the tip, I'll try that as well.
thirteen is offline   Reply With Quote
Unread 01-26-2009, 07:10 AM   #11
thirteen
Registered User
1996 ZJ 
 
Join Date: Jan 2009
Location: Pennsylvania
Posts: 17
Ok, I can confirm that my cruise control DOES work. I did take a cursory look at the vacuum lines anyway and everything appears normal. What else should I check.
thirteen is offline   Reply With Quote
Unread 01-26-2009, 07:23 AM   #12
Kruzin
Registered User
1993 ZJ 
 
Join Date: Aug 2007
Location: Casper, WY.
Posts: 3,144
Could still be a vac leak.
My cruise works...to a point...But going up hills, it will not accelerate enough to downshift when it needs to (not enough vac to pull the accelerator all the way down, already tried replacing cruise actuator).
My heater will only blow out the defrost.
I know it's a vac leak, but just been too lazy to track it down.

It could also possibly be the vac actuator on the heater box under the dash is bad.
__________________
DD: 98 ZJ Laredo 5.2, all stock

Wheeler/Beater: 93 ZJ Laredo
4.0, AW4, 231 conversion from 249
3" coil lift, JKS Adjustable Track Bar, JKS Quicker Discos, KOR lwr rad supt, Brush guard
Colorado Jeep Club Member 242 (4.0L)
Kruzin is offline   Reply With Quote
Unread 01-26-2009, 08:30 AM   #13
walter_da_jpr
4.0 Piston Skirt Victim
 
walter_da_jpr's Avatar
1999 WJ 
 
Join Date: Apr 2004
Posts: 1,302
As mentioned above multiple times, its a vacuum issue.

I have one vacuum line that likes to pop off of the intake from time to time even with a hose clamp. The heater will then switch to its default mode which is the defrost/floor setting, and you will loose cruise control function.

So check your vacuum lines for loose connections or leaks!
__________________
WALTER

Last edited by walter_da_jpr; 01-26-2009 at 08:47 AM..
walter_da_jpr is offline   Reply With Quote
Unread 01-26-2009, 08:42 AM   #14
djannello
Registered User
 
Join Date: Apr 2008
Location: Cleveland County, North Carolina
Posts: 114
In my 95 it wasn't a vacuum issue, but an issue with a little redirector door in the airbox itself under the dash. I've yet to fix it, but there was thread on here a while back that showed where you could push with a screwdriver or other implement (I used a ruler) once you set it to like face and it will stay there. I believe mine is caused by a broken piece of plastic inside the box itself, but haven't cared enough to actually pull the dash apart and try to fix it. Hope this helps.
djannello is offline   Reply With Quote
Reply
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.