2010 Mazda Mazda6 - dead battery and heater

power drawn dead battey /all the time
isues with heater not working at all

Find and fix the parasitic draw first.
Then deal with the heater, likely a blend door issue.


When you are able to get it running, take it for a drive to fully charge the battery, then the engine is off, car parked, keys removed, check to see if any lights remain on. Common culprits are the brake lights, lights in the glove compartment, engine compartment, and trunk. Interior lights of course.

Is the check engine light on?