I'm reposting as my earlier post was combined with another in error.
Although I don't need it often, my heater is not working. I have set the temperature controlwheel warmer than outside temperature and pushed the automatic button. Even set for high temperature, the air conditioning still runs and no heat is generated. The engine runs at the correct temperature. Although I could probably get along without heat I do like everything operational. Any ideas that a diy can do?