I'm still really interested in installing the sensor/display from an older Mercedes since I couldn't get the etacts changes to work, I asked on my Mercedes forum about how much current the sensor pulls and they said:

"The sensor is a resister, the resistance varies with temperature. Measure the resistance of the sensor and use it to divide 12v and that will give you the current. Very little."

I want to ask how I would get power to the unit via the cables that are made for the Mercedes connectors but I feel like I need to just get it and show you all what I'm working with. It shouldn't be that difficult I don't think...