Scotty, I have a 1995 Lincoln town car. I have owned it for 1 years now and the A/C nor heat have worked. In hunting down to find out why.
The picture will help you get the idea.
When I undo the vacume line I then get heat. What will cause this to happen?
Note: I have replaced the HCV and dose the same.

OK, the vacuum is to turn heat on and off, you remove it you get heat, that means the control unit is bad telling it to turn the heat off all the time

Thank you so much. They don't make those anymore last I hurd

Yep, will need to find a used one, just be sure there isn't some other issue at the hvac controller, like a disconnected or broken line for the heater valve control.

All the vacume lines seem to be intact and working. I will see if I can get this one rebuilt or find another one that is in working condition. In sure that will be a hard task.