Toyota Repair: heater, heater tubes, thermastat

Question
i have no heat i changed the thermastat but still no heat i checked the heater control it seem to be working fine.1990 camry auto.i replaced the heater tubes a month ago .

Answer
My best guess, given the information I have, is that the heater core may be clogged, check the radiator, if the coolant has a lot of rust this may be the problem, try to find a repair shop that can try to flush the system with a machine and see if that helps.