1989 Southwind Heater controls

This weekend I tried the dash heater on my 1989 Southwind for the first time sense I bought it. It puts out heat but only in my face. It would not change to the floor or defrost. I would like to know what type of system it has before I get into it. Does it use vacuum, mechanical or electric motors controls? I know it probably not electrical (to old). It looks like what you would fine in a Dodge or Chevy truck of its age.

Thanks

Buster