HElp defrost is only vent that seems to work on my '95 Cherokee. The selector arm moves normally through all the settings but only when it's on defrost is there any air movement.

 

Please use Tech write up submission for doing write ups not for general questions.

 

Your HVAC controls are vaccum operated, check the connection at the vacuum bottle.

 

ya, when the vacuum is lost defrost is a fail safe. it goes to defrost with no vacuum. and it uses vacuum to move the doors to change levels.

 

Thanks for info guys. Great forum. I'm a 1st time poster so sorry for posting in wrong place, I'll use tech write up next time. Looks like my cruise control is working intermitently which I understand is also related to vacuum reservoir. I located reservoir under passanger head light tucked into the bumper. Any hints on how to access and replace it?
Thanks
RMPD

 

might not be the resevior itself. first check for disconnected, broken, or damaged vacuum lines.

 

Resevoir never goes bad unless you crack it. There is probably a line somewhere broken or pulled loose. Did you look at the vacuum motor for your heater/A/C controls. Mine came off when the weather changed until I used a tiny tiewrap to secure the thing in place.
You never told us what year your Cherokee is so if it is over 10 years old the vacuum lines are likely toast and need to be replaced anyway.

 

diagram of vacum line and must just did it when the temp changed how did u fix you r blue??