[imjeepinVA]

I've got a 2002 TJ, bought last week, very little air comes from the panel vents, (the ones above the radio, and the one on both the driver's and passenger's side).

The floor vent and the defrost vents have plenty of air coming out, and at times the panel vents blow pretty well, but sometimes not at all. Without even moving the selector knob, the air will stop from the panel vents and move back to the defrost and floor vents. Anybody know what I should check?

Regardless of where i put the selector knob, I can't keep air to come consistently from the panel vents. There is also a whistling noise that comes and goes from the blower.

Any ideas how to fix?

Thanks.

[stogie25]

I hope this helps anyone whose vents and or heat doesn't blow, or anyone whose vents stop working when entering the highway or going up a steep hill.

I am the original owner of a 1997 TJ. I (also known as the loose nut on the steering wheel) am one of the few original pieces left on my Jeep. Recently I have discovered several other pieces of original equipment, all of which control the direction of air from my vents and heater. My tale starts about five years ago when my dashboard vents stopped blowing. My under dash heater and defroster still worked, so I just blew the problem off. This year my under dash heater stopped working, leaving me with only the defroster. Something had to be done.

I started at the control switch. I found the vacuum lines attached to the back of it, and blew them out with a football needle and my garage air compressor. I also found a splice in the line behind the glove box. I cleaned that out as well. I insured that everything was correctly seated and tried the vents and heater. No dice.

Undeterred, I started poking around under the dash. I discovered three vacuum activated switches with arms attached that control the air direction. They did not budge when the control was set to either vent or heat, and the input to them showed vacuum on the gauge. I was able to manually move them, thereby changing the direction of the air. I knew I was close. I contorted myself into a two hundred and fifty pound pretzel, and changed them out. This took about an hour, and cost about a hundred dollars. To my great disdain, there was still no air blowing through the vents or under dash heater. The switches at least tried to move (a definite improvement) but it seemed the vacuum was not quite strong enough to move the arms.

I crawled back under the dash and traced all the vacuum lines, identifying the black one as the source vacuum. It penetrated the firewall on the passenger side, not far from the battery. It went to a three way junction. One of the lines from the junction went predictably to the intake manifold near the rear of the drivers side. The other line went under the battery where it was broken. I sealed it up with a nail. Upon checking, I had full control of my air direction.

This did not feel like a complete repair with a nail plugging up a mystery vacuum line, so I perused a used car lot nearby and found another 97 Wrangler. I crawled under and traced the line to a vacuum reserve container near the bottom of the Jeep. My next stop was the auto parts store for a few feet of vacuum line. The problem seemed to be fixed.

That night I went to pick up a friend to take to the bar, and when entering the highway my vents stopped working and defaulted back to the defroster. As soon as I let off the gas a little it went back to vents. I remembered the Jeep doing this many years ago when the vents worked, and remembered that it was annoying then. Now I was emotionally involved with this repair and had no intention of letting this annoyance continue. I searched the internet, and learned that I was not the only person with this problem. I could not find anyone who had posted a solution. The internet was of some help, as it directed me to a Jeep TSB that told of a one directional vacuum valve in line with the feed, but did not give a part number. I called a friend at Jeep, who informed me that he had the same problem. He hoped I was successful at finding a solution for both of us. He diligently kept working on his part the solution until he found a part number from the Cherokee, which we figured would work. Due to the remote location of my friend at Jeep, I had to stop by a local dealership to pick up the part. It cost about seven dollars. While at the dealership, I told the parts people about my problem, and asked if they had ever heard of similar problems, and they told me that the Grand Cherokee has a small reserve reservoir in line with the vacuum source supplementing the larger reserve container. For another eleven dollars I figured I would try that as well.

I got home, replaced the valve, which was a slightly different part, and installed the in line reservoir, which plugged directly into the valve. I test drove the Jeep several times on the highway, and was unable to make it fail. I was also able to turn off the motor with the key in the accessory position, and keep the vents blowing, something I don’t ever remember the Jeep doing before. It is supposed to snow tomorrow morning, and I look forward to having the heat blow at me for the first time in years.

Check valve 4549209 $6.54
In line reservoir 4677204 $11.06a

[dz1087]

Originally Posted by stogie25

I was also able to turn off the motor with the key in the accessory position, and keep the vents blowing, something I don’t ever remember the Jeep doing before.

Mine did this a little when I had my foot on the brake. As soon as I let off the brake, it would stop blowing. Really bothered me since it was obviously some sort of elec. short somewhere.

Anyway, my TJ actually blows a little air out of the floor vents in every pos except defrost. Might have to check this out tomorrow.

[ben8jam]

Originally Posted by imjeepinVA

I've got a 2002 TJ, bought last week, very little air comes from the panel vents, (the ones above the radio, and the one on both the driver's and passenger's side).

i have the exact same problem - bought a 2000 TJ couple weeks ago and the blower blows fine on defrost and foot settings. however, the panel vents are pretty useless... haven't taken the dash off yet to check...

sorry not much to add except you're not alone

[kloppk]

I went thru a similar problem with my 97 except it was the defroster that acted up.
Here is a picture of the 3 vacuum actuators (for a 97) under the dash above the gas pedal.
Check to be sure they are all connected properly and push/pull the respective arms that control the dampers in your heater box. You'll probably find one that's dangling down when it broke off. The plastics arms get old and fracture easily.

[Dogman]

http://www.jeepforum.com/forum/f9/air-vent-problems-66176/?highlight=broken+heater

[imjeepinVA]

okay i found my problem, to the driver's side of the battery and down about 8 inches there is a one inch plastic pipe sticking out about an inch into the engine compartment, then i've got about an 1/8 inch vaccum line that goes in there, the rubber was cracked creating a leak..... well my problem isn't completely solved, how is this vacuum line supposed to connect, it appears that mine was just laying in the 1" pipe, and you can feel a vacuum around the 1/8" pipe so it is still leaking....

like i said, i've got a little 1/8" vacuum line sticking in this one inch plastic pipe, am i missing something is there supposed to be a connector at the end of the plastic 1" pipe for the 1/8" vacuum line to hook to.

any help would be appreciated. again it is an 02 TJ thanks.

[stogie25]

Posting a picture of that area would be a big help.

I have modified mine enough with dual batteries, new vacuum lines for the vent controls and all, that a picture of mine would probably not help you much.

[imjeepinVA]

okay, here goes, these are some pictures i took tonight, the area in question is hard to get to so it is also hard to photograph. The first picture shows the actual small vacuum line, this is the line that had a slit in the side and was leaking. The second picture shows where, the vacuum line goes, or at least i think this is where it goes, it is a 1" plastic stub sticking into the firewall, you'll notice that the small vacuum line has a little bit of an elbow on it, so i'm guessing that there is another part that should be on the end of the 1" line that i don't have. I can stick the whole line up inside of the 1" pipe and the vents will work for a little while, but you can still feel a vacuum around the small line, and it'll eventually come loose and i'll be back to square one. Any thoughts on what i'm missing here?

http://i262.photobucket.com/albums/ii97/imjeepinVA/VacuumHose.jpg

http://i262.photobucket.com/albums/ii97/imjeepinVA/Firewall.jpg

[stogie25]

I just went out and looked. The 97 has a 3 way splitter with one leg going to the vacuum reservoir, one leg going to the intake manifold (the source of the vacuum), and one leg going into the firewall for the vent controls. The 97 does not have the same setup as yours as the hose just runs through a hole in the firewall, but it is in the same place. If you connect that up, with maybe a tie wrap holding it tight, and some RTV to help seal it, and you have no vacuum leaks it should work.

If that does not work, look around car lots for a Jeep of your year, and ask if you can look under the hood to see what yours needs to look like.

Good luck