heat and ac display just blew out

They fail in time, LCD's do not last forever. Vibration, voltage spikes and heat variations cause wear and tear on the physical components of electronics. Sorry it broke, but you didn't do too bad, the car's 19 years old! You'll need to call a Lexus specialist or an auto electrical shop for help getting replacement parts or repairs. Here's a directory link for you: https://repairpal.com/lexus-repair-in-edgewood-maryland