Ac works good, blows cold, heater blows cold when I turn everything over to heat mode. Even after the car is fully warmed up.
Then the engine would not reach an operating temperature. OP stated that his car is fully warmed up, and the temp. gauge stays consistently in the middle. So it seems that the heat generating system is good, and the culprit is the heat delivering system (heat core, blend door etc.).Thermostat stuck open?