Hi all - I have a 59 544, the heater controls are misbehaving and I'm burning up!

There's a cable that runs from the bottom lever to the flapper that directs the heat to defrost or heat (near heater core).

From this image, I think that's backwards:
http://www.swedishtreasures.com/124.jpg

The cable that runs from the top lever goes to a metal housing near the gas pedal, looks like there's a heater valve in there?

I'm confused, since it looks like the heater hoses go to the core in the engine bay. How does water get to the valve?

A schematic would be greatly appreciated. I believe the control valve is just stuck, how is it accessed for servicing? The only access point I see is a 1" hole where the cable goes in.

Thanks!