mileage flashing & heater not working
Aren’t you still within the warranty?
Whoa, whoa, slow down with the overwhelming torrent of information there…

Is the speedometer working?
Posts from the link below say the flashing could be cuased by
- steering control module problem
- forward collision camera problem
- fuse problem
I see some others adding
- Bluetooth problem
- CAN bus problem
- Using a scan tool incorrectly
Good idea to do the basic battery/alternator test. Before first start of the day battery should measure about 12.6 volts. Immediately after starting the engine, 13.5-15.5 v.