@skrotz They were sadistic. Black = 24v, Dark grey = ground, light grey = tach, and white = pwm control. PWM needs to be inverted. Hooking up 24v and ground to an always on fan port and control to fan2 ground works fine. It puts out a ton of air, but the shroud spreads it out less than I expected.
I haven't confirmed tach as working but seems likely it would, although I'm not sure it's useful.