[rhandwor]

If the heater core is plugged you can check by disconnecting the hoses at the engine and put a hose on one end if the water flows freely it isn't plugged.
I would check if you unplugged a vacuum hose when working on the engine. The heater control has dampers which have to open. the have vacuum operated cylinders which open and close them.
Feel the top and bottom radiator hoses you could have a bad thermostat.