From that explanation, I would guess that the factory pot is connected (on the high side) to a fixed DC voltage source, typically 5VDC. The low side is connected to common (ground) and the wiper arm picks off a DC voltage between 5 and 0, and injects it into the variable voltage source to adjust the output. Very typical for a DC power supply. Your plan is to replace the pot with a temperature variable resistor to control the output via temperature. I would think that a series combination of two thermisters connected from high to low, with the center point of the thermistors connected to the injection point would also work and would give you more variability. Just thinking out loud, so to speak.
