Chrysler Repair: Lebaron heat/ac air distribution problem, vacuum leaks, thin plastic tube

Question
Hi Roland, I have an issue where the A/C/heat selector is could be on floor, could be on defrost or anything in between and all the settings result in air coming out of the defrosters.  Any idea why?  Vacuum leaks used to be common problem for this, not sure if that still is the case.  Thanks,

Answer
Hi Paul,
You are correct that the failure to respond to requested changes in air duct distribution is related to a vacuum issue because those doors are powered by an intake manifold vacuum supply line. It branches off the large vacuum line from the manifold to the power brake booster cannister, right at the cannister. It is a thin plastic tube that is routed to the center of the firewall at the level of the interior air distribution/heat/ac housing. Chances are the line is disconnected at the branch point "T" or is cracked somewhere along the path to the control switch in the interior console. So if it seems OK in the engine compartment side then look for it under the dash where it has a check valve and then attaches to the air distribution control.
If that doesn't fix it the write back and will some more.
Roland