Got an odd problem here. Got my vacuum line to the canister all fixed up so my air no longer blows to the defroster vents only. Everything seems to work as it should (well, no A/C, it's dead) - when on "vent" air blows out the correct vents, when on "heat" air blows out of the vents on the center floor, and when on defroster it will blow air to the windshield area.

Here's my issue though - when I turn the slide control to "off", moving down the road, air blows into the cab through something on the passenger side under the glove box area. This is the only time air comes in this area - when the blower and everything is "off" going down the road. It's like turning the climate control to "off" opens a door or something.

I do not believe this is a vacuum related issue.

Any ideas?

 

Anything missing in the firewall? Is it coming through the floor heating vent?

 

No, it is not coming in at the heat vent on the center hump.

It may be coming in under the glove box area, there seems to be a flap under there that opens when the air is turned off.

 

The flap that opens is covered in foam, is this the blend door that people talk about? Anyway, when it opens, I see the blower. So I opened the hood to look down the firewall at the blower, and I think the previous owner may have left the blower cover off! I suppose that would let air blow in going down the road.

I can't see good due to the windshield washer fluid jug, but I do see a black center cone type thing and a couple of wires. I think that's supposed to be hidden by a cover?

 

Not really too sure about Jeeps (just bought my first one) but I know many vehicles do not close off tight. There is always air circulating to keep fresh air in the cabin. To me its kinda of aggrivating but it may just be the way its designed.

 

Ok, did some testing today in my dad's '96 XJ. Air blows from the open foam covered door in front of the blower motor when climate control is set to "off" in his, too. However, in his it was a lot less blowing than mine at highway speeds.

Since the blower is not blowing air, and it's strictly air coming in from forward movement down the road, where could extra air be getting into my vent?

 

That air is coming in from the cowl of jeep. This is the area where the wipers are located. On passenger side you will see all the holes the fresh air inlet is down there.

Weather conditions can affect this. Such as driving into a strong head wind. That door u see behind glove box is called the recirculation door. When closed air is drawn from wiper cowl location, and open draws air from inside jeep and back out vents. Normal position is closed.
I done imagine there is not any thing wrone.

 

So it is normal for the recirculation door to be open when the climate controls are off?

I just had the windshield replaced, but it sounds like there is nothing there to get messed up.

Thanks!

 

Same thing for mine. I traced all those pesky vacuum lines. My air was coming from the floor as well. Right side of the bumper, behind the plastic well liner, there is spherical canister. The right angle boot was broken. I replaced it. The air worked beautifully as it should have.

The catch: within 2 minutes of repairing (resealing the HVAC system), the SEL came on. WTH??? Much research concluded that, the HVAC system is part of the emission system. WTH??? Since air can be polluted by combustion, and since the HVAC draws air from the same source as the combustion components, it is part of the emissions system.

Apparently, since the XJ accounts for the degradation of certain emissions measurements over time, and since the AC vaccum had been leaking for so long, the increased air flow (to the intake and subsequently to the O2 sensors) became the norm and all emissions components were graded the same over the time span. Once the HVAC vacuum was back to normal, the degraded O2 sensors readings did not match up with the readings from the healthy vacuum, and thus appeared dirty and fouled and, thus the SEL lit.

Replace the O2 sensors, right? Did it. More SEL followed. I replaced all parts except that little box under the back seat. In the end, my inspection ran out, my patience followed, and the XJ rode both their coattails to Carmax, where, I bought my wife a beautiful Saturn view. She loves it and me too now, for, she hated me and my jeep.

The jeep was junk anyway, been hit three times and sucked more air into the cab than a nerd who got punched in the solar plexus.