[tlorber]

Even though the dial on the gauge is mechanical (i.e. not an electric display) the gauge is still considered electric since it sends and receives via an electric signal. A true mechanical gauge uses a probe with a capillary tube filled with some kind of solvent that physically expands and contracts and moves the dial as the temp changes. I'm not sure if that addresses your question, but my old temp gauge was a true mechanical one. It actually still functions well but I was trying to modernize the dash for practical purposes, and I wanted fewer holes through the firewall.

I'm not quite at my fan controller but I have a feeling I will probably need to tap into a different point in order to actuate the one I plan on using. It converts an on/off fan to a variable speed fan.