I have a 99 Xj and blower motor was being weird and i just replaced it today, part under up rubbing on the inside and didn’t work so i put the old one back in and it worked how it should but has a slight tick now, After doing all of this my selector to change where the air blows is stuck on only defrost and won’t change at all and i’ve seen posts about how it’s a vacuum leak but i can’t seem to find what the right line is for it or how it should look, i heard about the big ball thing that has the 2 lines running through it and mine was moved to just sitting in the engine bay from the old owner so i don’t know what i should be looking for, please any suggestions.

 

I'd check the vacuum lines around the firewall as well as anything that's been "modified" in relation to relocating the vacuum accumulator ball. Also if you pull the radio you should be able to access the back of the climate control switch block, maybe you tugged on something and pulled one of the many lines out.