Does your fan turn on? One thing you might want to check is the flap that controls the air flow direction . That is what was wrong with mine. Look on the heater unit below the dash. There should be a cable on the left side of it. That controls that flap. Move it all the way up and it will on defrost. Also check the hoses and the heater core itself. One other thing that was wrong with mine is the hoses that go into the cab have a valve to let the engine coolant into the heater core. Check to see if the valve is stuck shut. If so just get some dw-40 and spray grease and loosen the valve and hinge. Sorry for the essay.
i got my heater working finally so its not cold nomore it was the lines that go into the heater core i figured it was somethinh simple like that
