Different AC problem

I see a few guys on here having intermittent AC problems. I am also having intermittent problems but they differ somewhat. My AC doesn't quit working, it just changes which vent it comes out of. It seems that if the engine is under load, such as pulling a hill, it will stop blowing out of the top vents and start blowing out of the defrost vents. If I let off the throttle and coast for about 5 seconds, it will start blowing out of the top vents again. Got me baffled. Any suggestions?

Check the vacuum line next to your battery. It goes to a vacuum canister in the front bumper. You need the canister for when the engine puts out a low vacuum (such as high rpm, under load up a hill.) It goes out the defrost vents when under load because this is the default for the vents when there is no vacuum.

What year XJ? Are you having problems with cruise control/CAD also?

It is a 98xj sport, 4.0. I have had it for 3 years and the cruise control hasn't worked since I've had it.

the same vacuum canister is responsible for supplying vacuum for the C.C. as well-- all signs point to a damaged vacuum line or a damaged vacuum canister.

Yup. The line running from the canister goes in between the battery and passesnger fender. The vacuum line usually dries out and cracks, either caused by age or leaky battery acid (or a combination of both.) My bet is on that line. A simple $5, 5 minute job and you will have a proper functioning HVAC system as well as your cruise back. Good luck

Thanks everyone. I will definitely take a look at that line when I get home!