Is this a thermostat problem or computer problem?

What is your question?

I changed my headlights in January, unplugged the battery in order to do it myself. After reconnecting, had to reset the seat memorys, power windows, that normal stuff. But since then, sometimes the thermostat above the navigation reads the wrong temperature, or will read in Celsius while the thermostat near the odometer reads the correct temp. Also, the A/C won't blow heat, will not blow hard, and no matter what directional setting, will only blow out of windshield defroster and a little out of the middle vents. Air works and but for the first 30 seconds to 1 minute that the car is on, it won't allow me to turn on the A/C. The windshield defrost button will just blink. Also, if I have the A/C running and turn the car off, when I turn it back on, the A/C is back off. Toyota told me I need a new thermostat and coolant flush but my old Mazda dealership I worked at that new very little about Lexus said it sounds like Toyota just wanted my money and it doesn't seem like the problem is the thermostat.