RE: AIR VACUUM LEAK??
Barry,
The blend door has absolutely nothing to do with the vacuum system except it is controlled by the same ETAC control module. The blend door is electrically operated and monitored electronically by the ETAC control module. So, don't blame your dealer just yet. I have done the blend door replacement on my '98 twice, and maybe they pulled out or broke a small plastic vacuum line when they replaced your blend door. There are some hoses in the general area. Most shops cut a portion of the dash instead of removing it and they also may have pulled it out too much disconnecting a connection as well. I assume you did not have this problem before they replaced the blend door, and have not had an accident to your passenger side front - specifically around or behind the right front wheel. If not, proceed.
Your best bet is to get a vacuum pump and guage from a local auto store. First remove the battery's negative connector. Next, pry on the bottom panel using your fingers (panel with the with the rear defrost switch on it). It should pop out. Then, remove the 2 screws holding the large plastic woodgrain panel which is then removed by pulling it out and up around the radio, ETAC controller, and the gearshift. It has strong springs, just pull. It may help to place the gearshift in different positions, so have the key in off or run. Remove the ETAC controller by removing 4 torx screws and disconnect the 2 electrical connectors. Remove the two end nuts to the vacuum harness connector to release the vacuum lines from the rear of the ETAC controller. You will have to pry the hose connections away from the controller as well. There are four connection ports that are attached to various vacuum motors and one connected to the vacuum source. They are all color coded. Connect each vacuum line up to the pump and pull a vacuum on it. It should hold a 15 psi. allowing for 1 pound of vacuum per minute for leakage. If you find one that doesn't meet specs, that's your problem. Do the center vacuum source port as well. That should take more time to pull the vacuum, but again, it should meet the above specs. If you find a leak, you may have to purchase radio removal tools to get the radio out in order to fix the hose(s). One hose goes around the middle of the heater A/C plenum and is a "feel and replace" connector. One hose goes over to the blower motor area and one motor in the front has 2 hoses connected to it.
As you look into the vacuum connector, start at the very top and go around clockwise. These are the Lincoln numbers:
#1 (12 o'clock position) - Not used.
#3 (2 o'clock position) - Blue, the Heater Air Damper Door.
#6 (5 o'clock position) - Red, Heater Air Damper Door.
#4, (center of connector) - Black, Vacuum Source.
#5 (7 o'clock position) - White, A/C Inlet Duct Door.
#2 (10 o'clock position) - Yellow, the Windshield Defroster Door.
Ports 3 and 6 go to the same vacuum motor, but there are two different connections on it. Make sure that the Blue hose (#3) is connected to the end of the vacuum motor and the Red hose (#6) is connected to a the middle of the motor.