Headlight loom upgrade

Howdy partners,

I am in a little dilemma and might need to enlist the help of someone in the know. I am rewiring my headlights with thicker wiring and dual relays and the rest. I have it all in the vehicle and set up, but i just cant get high beam to work, it just stays on low beam.

See i cant work out what wire i take as high and what one is low on the headlight plug. H4 plug by the way, vehicle is Mazda BT50.

When i test it i get,
No power when lights are off or on park lights.

2 outside plugs have power when low beam is on.

Middle plug and one outside wire has power when high beam is on.

Sorry but i dont understand it, is that negative or positive switched or is it a mixture of the two? It seems that the outside terminal that has power regardless is the low beam wire, and its earth is the middle wire, but when switched to high beam the other side of the plug becomes the high beam power and low beam becomes its earth?

Im a little lost, so i've probably just confused the hell out of you too. I just need to know what kind of positive/negative switched system it is and then which wires i would take to trigger the relay for them.

Thanks for any help that can be offered. I always thought it was positive switched so i could just run 2 trigger wires from the 2 outside terminals on the plug, but this isnt the case.

Cheers