I have prety much the same story - out of warranty and driver's side heating and cooling not working. They identified the issue as a part which I have now bought and will be installing next weekend. Temperature Controlled Seat Blower Motor - Ford (DU5Z-19N550-D) https://t.ly/NSjnT
Thanks for posting these details.
I have a similar issue - heated seat driver side no longer working (on the bottom - back-rest part of seat is still actually working).
Anyway, dealer said its the blower motor. Part = €139+Tax . . wait for it . . labour = €500 :O so I'll be ordering the part...
I'm based in Dublin, Ireland.
This is a used undamaged, front bumper with all fittings, fog lights and grills.
We replaced (customised) the front end of our 2018 Ford Mustang S550 Mustang
Postage to be agreed upon sale.