I spent some time going through the disassembly for $42 and it looks like the existing throttle kicker logic can be configured to control an electric fan. The problem is I cannot find a schematic that shows which pin is used to control this.

It's referenced in the '746 disassembly and $99 too, all sharing similar hardware, but it doesnt show up on any schematics I can find online.

Any ideas before I go crazy and start probing outputs?