I found the answer why my HVAC controls were "sticking" in my owners manual.
It says;
"Under normal weather conditions, do not leave the air flow selector in
MAX A/C or OFF when the vehicle is parked.
This allows the vehicle to “breathe” using the outside air inlet vents".

This video may help you if your car has the EATC (Electronic Automatic Temperature Control) unit;
   • Ford EATC HVAC Self Test  Reset & Ca...  

Disclosure;
My YouTube Channel is not monetized. I am NOT an Amazon Affiliate, I make no commissions of any kind. I make these videos for fun. This channel is dedicated to owners of Crown Vics, Grand Marquis, Lincoln Town Cars, and Mercury Marauders.
I make 3 types of videos;
1.) DIY tips on maintenance, repairs, and modifications like LED lighting.
2.) Product reviews of Panther Platform related parts & accessories.
3.) Q&A videos answering questions about Panther Platform Cars.
Email questions, or comments to: [email protected]
(Rev. 2/6/21)

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