Nissan Micra heater control?

Hi.

Having some trouble with my 1999 Nissan Micra. I think the dials on the heater control panel are faulty.

The first dial (the on wich says where the air comes out) will only rotate halfway around. the other 2 can rotate as normal but they do nothing and no air at any speed or temperature comes out.

Any ideas on what is causing this and how it can be fixed.

thanks