I test drove a 2013 Mazda I sport with 100,000 miles. No dash lights, smooth ride, no weird sounds.
The heat was warm but never got hot and it had been running 5-10 minutes before I got in. With gas on highway it was still only warm. The air blew out strong too.
Anonymous
Heater core could be clogged or blend door actuator could be bad. A mechanic will tell you which is the culprit.
thebax2006
You need to take the radiator cap off and see if the coolant is full. Run the motor with the radiator cap off to see if air comes out of the radiator. it sounds like an air pocket in the heater core. It might be from a head gasket starting to go bad.
Hickory
Check the antifreeze level, then the A/C. Start simple with the fluids then move up to a system problem. If it has no dash lights it may be just a fuse but it is possible that a module controlling multiple functions needs replacement.
Also check the heater core for leakage. The appearance and smell of antifreeze is the most obvious indication of a heater core needing replacement.