I answered this question just a few prior, but you have a vacuum hose leak. The defroster vent is the "default" setting when this occurs. Open your engine hood, look slightly left of center up along the firewall. There is a really tiny black hose coming from within the firewall that "Ts" into another hose. It's hopefully broken where visible. Use a piece of tubing like a splice and fit the original ends into each end of the new piece. If it's broken on the other side of the firewall, the entire dashboard will have to be pulled. And I've both read and been told that's not a job for mere mortals to tackle. But take your time and look around. And be gentle 'cuz you don't want to screw up this very tiny piece of tubing. Good luck.
you need to replace the vacuum.
Check for vacuum leak either under the hood or under the dash Check the operation of the vacuum actuators Check the selector switch Defrost is the default setting on this system
the mode door inside the hvac unit has most likely broken causing to to default to defrost. sometime the actuator is at fault, wither way the dash has to come out
when it happened to mine, it was because the arm behind the dash that controls the internal vent doors slipped off
they are on the front panel, left of wheel and right of passenge airbag, really small looks like the vents
They should go up to the right front fender. they are just air vents
I would think that is a vacuum or a linkage problem with the heater control assembly (where all the buttons/slides are for changing between floor/defrost/vent) Had a diaphragm go bad on one once, and in a jeep cherokee, a slight collision with a guard rail knocked a vac line off for the vent controls, and ac only worked from defroster.
Vacuum leak in one of the hoses I own a Jeep Cherokee Sport, found that a broken vacuum hose was the culprit. When there is a vacuum leak, the blower-ventilation defaults to blowing through the defrost vents. Once the vacuum lines are fixed, the other ventilation doors are able to function and open. Your set-up and placement of your lines may be different, but mine were located in the front-lower right of the engine compartment, running up the right side and ending in the back/firewall. The lines are cheap and easy to replace, took about 5 minutes and 3 dollars!
Either you need to pen your vents or there is some vent obstruction.
Leaking heater core
hi i like nomey
Compressor will normally run when in defrost mode.
rear wiper, rear defrost
Your air mix door is stuck or broken.
The acturators that control the defrost and vents often become inopterave because the mechanical link from the acturator to the divertors breaks. You can see if this is the porblem by looking just to the right and above the gas pedel. I have just tryed adding a screw and some glue to see if that works. The only problem is, that I had to remove the entire dash to get to the diverters and acturators. About 4 hours so far. But I am a shade tree machamic.
A 1998 Jeep Cherokee has disc brakes in the front.
The popping sound is most likely caused by a problem with the suspension. The front strut spring is the most likely culprit.
One possibility is a brake caliper that has a broken or missing bolt. Or something has broken inside the front axle.
The 2010 Jeep Wrangler has 41.0 in. of front leg room.
The 2011 Jeep Patriot has 40.6 in. of front leg room.
The 2011 Jeep Compass has 54.6 in. of front shoulder room.
The 2011 Jeep Patriot has 54.3 in. of front shoulder room.
The 2005 Jeep Wrangler has 51.8 in. of front hip room.
The 2009 Jeep Wrangler has 41.0 in. of front leg room.