mgriep

Names marq new here! My a.c is stuck on defrost does anyone know how I can fix this? Shop estimates 22 hours of labor to fix a 15 dollar part?

cruiser54

Most likely an issue with the vacuum supply/storage system outlined in the diagram below.

tek610

Exactly what Cruiser said-

Look inside your front bumper for a small disconnected hose. Plug it back into the cannister.

Fixed mine in 10 seconds.

mgriep

So is it something I can fix going through under the hood or do I have to go through dash board? I was told they would have to take off the entire dash...

Programbo

The way Jeeps work is..If there is any break in the vacuum system that controls the heat/cooling etc it goes to the defrost only as the default setting. So somewhere along the line between the vacuum ball and the heat/ac control switches there is a break in the tubing. Just trace everything and eventually you'll find the break. Just as an example I had to take my battery out to work on something and when I reinstalled it the battery nicked the tubing running along the fender and that was all it took to make my heat blow out the defrost only

tek610

look underneath/inside your front bumper first- that's the most common place a disconnect occurs. If the little hose is connected to the vacuum reservoir, then the problem is deeper and more difficult to reach. If it's not connected, you've found your problem, without a wrench or screwdriver...

patnok

those little plastic hoses get brittle as they age.

mgriep

Awesome thank you so much guys!

Robert Ottavio

I have the same issue. AC is stuck on defrost.

I pulled out and replaced the switches and it didn’t fix it. I have no holes in the hose at all. (I smoke tested it). I changed the AC actuator and noticed that motor works for the heat/cool switch. I can’t figure out the problem.

Is there a motor similar that works the middle switches for defrost and AC? Maybe that motor is bad? I can’t figure it out. Any help would be great. Thanks

cruiser54

Ya know, the plastic reservoirs can go bad......

MaskedMallard

What year is your XJ?
Any front end damage?
Any right front damage?
Have you done any recent work on your XJ? If so, what?

ButtStripe

Had the same issue, it was a vacuum line that ran in front of the blower motor.

XJlimitedx99

Get a vacuum pump and test the system to ensure you do not have a vacuum leak before throwing any more parts at it. 99% chance you have a vacuum leak, or a check valve is bad somewhere. I had a check valve that was bad that took me forever to find. When removed I could only blow through it in one direction (like one would expect) but when pulling a vacuum it would not hold nearly as much vacuum as it should have.

RocketMouse

Ya'll can slap me if I'm wrong for mentioning it....but stating that this is stuck "on".... can it only be a vacuum issue? Or is it possible that compressor clutch could be stuck on instead or in addition to the defrost issue?