Air vent problem

I found a very small hose attached to a black ball like object the size of a soft ball. Hose has been chewed in half. One end is attached to the ball object and the other end goes through the firewall. I'm not as flexible in my old age, so I haven't made it under the dash to locate where it is attached. Not sure how to post a picture of it.

As Roger said, there is a vacuum switch controlled by the lever or dial on your dash. It is quite possible that one of the vacuum lines has come loose from this switch behind the dash panel. Check here first. If all the lines are connected, then it could be the switch itself. This was the solution to the same problem when I experienced it. $35 for the part but about two hours of cussing and swearing to access the switch and replace it?

Dear in advance,

Manual for 1988 Southwind manual

Hope that helps some.

Don't mean to sound stupid BUT, where would the vacuum lines be located? Thanks

HVAC systems at that time used vacuum to operate the flappers. If you lose vacuum they default to defrost mode (for safety purposes) which is what you are describing. Some place you have lost vacuum. There are several flappers in the system and the mode switch on the dash is a vacuum switch so there are many possible places to leak. It is probably due to age, but could be due to mouse damage. You will have to find and fix the vacuum leak.

When mine did that, it was that mice had chewed the vacuum line that activated the diverter that determined whether the air was foot, dash, or windshield. I forget which mine was stuck on though.

Cost was a few hundred dollars at the dealer to get the vacuum lines replaced.