[gthompson97]

The coolant travels from the radiator, through the motor, through the heater core, and back to the radiator I believe. I don't think that not having enough antifreeze would cause the heater to not work because the more water, the lower the boiling point so technically the more water you have, the warmer it *would* run if there was no thermostat to "monitor" the water temp.

I'm kinda stumped on what your problem is, but you're sure that it's full of coolant? Maybe you have air in the lines, or like an air lock or something like that like Dustin said?? But I haven't ever heard of that in our cars, or ever to be honest.