Heating *wierd*

[JeepTrouble]

I have a very stange issue going on with the heating of my 1990 jeep sport. The air conditioning doesn't work (go figure) but the heating leaks. You can turn the heater off completely but warm air will still come out, only through the vents up by the windshield.. It will not come out of the vents down by your feet, or the ones in the front of the dash. I have NO idea what this could be, it's just REALLY wierd any ideas?

[98_Classic]

might be a leak or break where the heat/air should go through.

[vamc]

Sounds like a vacume(sp) leak somewhere.

[Saudade]

The ac/heat system uses a set of vacuum operated doors to direct/divert the airflow based on your control settings. If there is no vacuum to the defroster door, it opens allow the airflow to exit the defroster vents. The doors could simply be stuck as well.

If you run the engine for a few minutes to build vacuum, then shut it off (assuming there no other loud noises nearby), you can hear the doors moving as you move the control lever. You can do this a few times until the vaccum equalizes.

I can access the one of the door vacuum actuators on my '88 from under the dash. It's tucked up on the drivers side, under the dash, right next to the floor duct. Mines a round metal canister with a bent tube coming out with a small hose connected to the tube.

I'm not sure which door this works. Assuming it's the floor duct, with no vacuum this door is closed.

[vamc]

I agree.