And btw, he believes the wintertime frost inside the windshield was caused by this situation.

Awesome news, glad you got it fixed!
Please do share the codes he found/cleared, they may help others in the future.
Glad you found a knowledgeable guy to fix the problem!

Awesome, sounds like he may have "killed two birds with one stone"

Thanks for bearing with me, and to all and anyone who gave some support!

So, here are the codes and notes he wrote, as well as I can read them. Btw, he said they were in the HISTORY, implying they weren't exactly current:

B0234 - Airmix D... Range
B0249 - Mode Door Range
B0269 - Air Inlet Door Range
B0279 - no note
B0179 - no note
B1004 - no note
B1328 - no note

ELECTRONS!!! OR ARE THEY HIGGS-BOSONS?