Ok, I bought a Breakout Box.

The aux cable has three wires - bare (assuming it's the ground), white and red.

I bought a multimeter. No idea what I'm doing but connected the assumed ground and then found no variation on the reading with the red wire and various readings and varying pump speed with the white wire.

What wires should I connect to which terminals? I assume the bare wire to terminal 3. White to 2? Red to anything?