Pinout for the fan connector
Bought a second hand A1470 and can see that someone has mangled the fan connectoion. The cable runs up the side of the chasis from the fan then splits into 4 wires, each terminating in a pin which should be inserted into the connector, then connected to the board. In mine the pins have been pulled out of the connector, and the connector is still connected to the board. I can't tell from the photos which of the 4 cables/pins goes to which of the 4 sockets in the plug.
I can see what I'm assuming are the wire crossing over in the teardown pics, but they're not quite at the right angle for to figure it out convincingly.