1999 Lincoln Town Car leaking on passenger side can see it running down carpet on the px side. It only happens if it rains or in pwer car wash. Help. Please

Faulty door gasket or HVAC case seal?
You may also have debris in the HVAC inlet that isn't allowing for proper drainage.
Try to determine if the leak is coming from the door area, the kick-panel area, or from under the HVAC case.
Let us know...