The Air, Cruise and Parking Brake all seem to be reacting to the SAME vacuum leak. I know this only because I've surfed the net for information and discovered that these problems are known to be interrelated on the Sedan DeVille.
1st: The air changes vents when I accelerate (From Front vents to Defrost and Lower Vents). When I return to constant RPMs (no matter what speed) the air returns to the forward vents (although even then there seems to be a lot of leakage to the upper and lower (vents)
2nd: The Parking Brake does NOT disengage when put into gear. This I understand is a clear indicator of a vacuum problem.
3rd: The Cruise will engage for a few minutes after starting the car. It will disengage within 5 to 10 minutes after engaging the cruise control. It will not engage again until after the car has been shut off, then restarted.
There are NO CODES concerning these problems!
Is repairing the vacuum system a big, complicated thing? Could the problem be something else? Please advise
832.257.7188 (TXT me if you like)
Yes, there is a vacuum line from the outside to inside that controls the items. There is a check valve that retains the vacuum for the doors. It may also feed the neutral saftey swtich for the e brake but there may be other issues with that as well.
The cruise is electronic and I do not believe it is related to your issue.
Go to a shop and ask them to check the lines and see if any are off or broken.