Edit: Got it! I loosely connected the wires, hooked up the battery, and flipped it on.
I’m trying to wire up a chassis harness to my embedded fuel pump. The harness is from Honda and uses conventional red/black wiring, but the fuel pump is European (French chassis but raced in the UK, so it could be a British fuel cell) and it has blue and white wires. I just need to figure out which one is positive and which is negative.
(The car, in case you’re wondering why a French car used in the UK has Honda wiring:)