Need help.Memory bad!

[1970duster440]

I bought a '70 Duster in April of 06 and brought most of it home in boxes. I'm working on the heater box. I have 3 control cable connections. I know 1 is for temp. and 1 is for either floor or defrost air flow. My memory from when I owned my '71 340 Duster back in '74 is pretty much gone :drunken:, was if there was another lever under the dash to turn the heat on and off or if it was to let fresh air into the heater core side. Help me restore my memory so I can start on something else while the car is in paint. Thanks :scratch::scratch::scratch::scratch:

 

[abodybill]

Two of the cables connect to the top cam.

I'm in the house and cars in the back barn but,one is for the defoster and shuts heat off and and doees the oppisite when pulled or pushed to what you need(heat/deforst).