A somewhat related question: Where is this interior temperature sensor and how difficult is it to replace? My '98 EX with 325,000 miles (nicely broken in) blasts full heat regardless of where the temperature control is set.

 

I moved this as it is a bit different than the thread you posted in.

Check for codes from the HVAC. I'd also check the heater contol valve to be sure it is closing off, visually and internally.