Direction of flow is controlled by the aforementioned cables, and did you say that it only works on high and off? That's just the blower resistor, where as off is no current and high is no resistance. The resistors for the other settings blew, just get a new one. I have the same problem on my hatch, I'm just to lazy/poor to get a new one, that and the goddamn window handle.

 

only one heat setting.....blower resistor
Not blowing out warm air......thermostat
All air being blown out behind dash......check the ducts