Heat only coming out of defroster vents

thirteen · 01-23-2009, 02:44 PM

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?

jetguy81 · 01-23-2009, 02:50 PM

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.

kmb0427 · 01-23-2009, 07:41 PM

does your cruise control work?

mdav8629 · 01-24-2009, 07:09 AM

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???

cmonson · 01-24-2009, 07:36 AM

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.

thirteen · 01-24-2009, 09:41 AM

Quote:

Originally Posted by kmb0427

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)

cmonson · 01-24-2009, 10:44 AM

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.

04WJGuy · 01-24-2009, 10:55 AM

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.

kmb0427 · 01-24-2009, 12:27 PM

Quote:

Originally Posted by thirteen

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.

thirteen · 01-24-2009, 01:14 PM

Quote:

Originally Posted by kmb0427

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 · 01-26-2009, 07:10 AM

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.

Kruzin · 01-26-2009, 07:23 AM

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.

**walter_da_jpr** · 01-26-2009, 08:30 AM

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!

djannello · 01-26-2009, 08:42 AM

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.