Re the design: button and icon styles look fine, I would only make two changes for usability:
1) make the secondary buttons (recirc, etc) and icons the same size as the others. Key in a truck is “glance-ability”… big enough that you can recognize instantly and poke with a fat finger while driving
2) the hard edges on the recirc and defrost are too similar. I’d make one of them (probably recirc) more obviously curved. Same reason as (1)
Minor nits though. Look really good, noce work improving the functionality
1) make the secondary buttons (recirc, etc) and icons the same size as the others. Key in a truck is “glance-ability”… big enough that you can recognize instantly and poke with a fat finger while driving
2) the hard edges on the recirc and defrost are too similar. I’d make one of them (probably recirc) more obviously curved. Same reason as (1)
Minor nits though. Look really good, noce work improving the functionality