Good news!!! Problem solved.
I had a bad vacuum valve switch that controlled the diaphram actuator behind that is located behind the glove box. I was fortunate that it was easy to access and not something that is tucked way behind the dash. By process of elimination I was able to narrow it down to the vacuum valve switch. I checked the PBU, diaphram actuator, source vacuum, and electrical connection to the valve switch, all checked out fine. When I tested the switch by putting 12v to it, it was bad. No one had the part locally, so I ordered it from PartsShop. In the mean time, I ran a vacuum line from the source vacuum to the diaphram actuator to allow air to flow.
The ambient air sensor tube was also bad and fixed that too. Thanks for all the help.
Tim