Heater box control cable

[Ahwahnee (Geo Hahn 1969 Series 2 OTS)]

Uhhh… Déjà vu:

Heater Valve cable

It looks like the heater valve cable for my car has broken off and was wanting to replace it. I have two questions. How hard is to replace? can you just replace the inner wire with out trying to fish the whole cable thru the dash. 2 has anyone came up with a heater valve that has the opposite throw, so that those individuals that live in hot climates do not have to have the lever pulled out to cut off the flow of hot water? I know most people just disconnect it, but I just like every thing t…