defrost vent only works on low....

Hi folks,
Hope you can help a Canadian on this one cause I can only run my heater on low and it's been about -20C here for a while...brrrrrr!

My heater will only blow air on my windsheild when it is on defrost/low. If I pout it on high I hear the flap close and it won't blow out the defrost. I've checked all my lines and I have a strong vacuum going to the line that goes into the cabin and the other actuators open and close.

question:
What is the likelihood that the actuator for the defrost is leaking?
do I need to remove the whole dash to get to it????

Hello,

My '99 does the same thing. I can hear the flapper door close when the fan speed exceeds 1. I can sometimes get speed 2 to work, but once you hit a bump the flapper closes. I just cycle between 1 and 2 as much as I can.
Must be a spring or something off. I have the HVAC section of the shop manual. It has a diagram of the air flow system and the flapper door which is likely causing the problem. I do plan on eventually getting to the flapper, but no time soon.

Let me know if you would like me to email you the .pdf of the HVAC section. It is about 850 KB.

later,
Ronnie

Email.that would be great.

Another thing I've noticed is that when I was able to get it going on another speed as soon as I accelerated the flap would close. This leads me to beleive that either the line to that actuator is leaking or the actuator itself is leaking.

What is involved in removing the dash?

btw it's a 97 xj

Happened on my '98

Good to talk with you guys again. Been a while.

This is what i discovered on my '98 w/ A/C: There is a vacuum motor above driver's wheelwell connected to a small bellcrank that controls the defr flap in the dash. That shaft the bellcrank connects to pulls out of the mechanism inside. You can simply push it back in and will work for a while, but will come out again. Is a pain in the a** to get up into there to do this each time. Had to remove the large wiring harness connector from it's mount and push aside to help gain access. After the third time it disconnected i made a clip-type bracket clamping onto one of the reinforcement webs of the heater box beside the belcrank that applies pressure to the end of the shaft. I guess is what you'd call rigging, but the alternative sucks. The dealer said the small, insignificant, piece of crap plastic shaft part was NOT available separately, that the entire heater box would have to be purchased!! Does that not sound like a typical dealer/auto mfg? Of course now that i have stated mine continues to work well for two years since that 'repair' it will break.....thanks a lot!!

Perhaps if others checked with their dealers they might find that shaft, maybe an improved one might now be available??

Good Luck.

I just replaced the hard plastic vacum line from the resevoir up to where it enters the firewall, with rubber vacum line. allthough there was no obvious damage, it made a huge difference. all my flaps and doors are slamming open and shut twice as fast. found this info on a google search.

Hey all
(first post here!)

did anyone find a fix for this?
my 99 just started doing this the other day, and now its gonna start snowing any day and i need to fix this.

anyone have any suggestions??

Most common problem is a vacuum leak.

My '99 did exactly the same thing. I reached up around up under the dash, from the driver's side, (like Judd W. VA described) and pushed the arm back in (firmly!) and it's worked fine for over a year.

sorry to be a pain guys, especially after just joining, but does anyone have a picture or something of where this arm is and how it looks? the dash is in pieces now, but i didnt remove the glovebox paneling

sorry I don't. It's right on the side of the box attached to the actuator. Mine was snapped in half so I glues it.

My '99 has been doing the same thing... I pulled the radio and realized that the piece of foam that surrounds the defroster box thingy had a whole in it. I duct taped the hole and I haven't had a problem since.... it's only been a day, but it blows on 4 no problem. One thing though, I cannot get any air to come out of the dash vents??

So all I have to remove is the radio to be able to get to this? or the whole dash and speedometer?

will it be clear to me once I remove that stuff what needs to be fixed? Id just like to know in advance before I take the dash apart again.