If I wasn't looking at the datasheet when I replied then I wouldn't have known that D+ and D- were analog inputs from the temperature sensor. That still doesn't answer my question as to what voltage = what temperature. One could also read off of the serial output of the ADT BUT, it is an average or 'mux' of it's own temperature sensor AND the sensor within the RSX. It's also easier to just take a voltage reading than to program a microcontroller or mess with a shift register and a bcd decoder.
Well, it's been quite a lot of time. I don't see this thread ultimately ending with a solution, so I just wanted to thank everyone for their contributions, and apologize for my gripes and groans. I guess I'll just have to wait and see if it breaks again to determine if it's been getting too hot or not. Thanks again everyone.