- red = +12V
- black = ground
Is a fair guess, but I would verify with a multimeter before connecting. Everything else on there is probably +5V and connecting power to it might fry it.
As for TX/RX pins: definitely a digital communication bus, probably UART and will be operating between 0 and +5V. Ideally, you would have access to an oscilloscope and you could test this, but I’m guessing you don’t. Flipping these shouldn’t matter and you’ll know if they aren’t connected correctly b/c (I’m guessing they feed the display) the display won’t work correctly.
The only pin I’m not sure about is the one labeled DS. It’s probably not above +5V, but I would check it if you choose to start start guessing which wire goes where.
I’m assuming that you’ve hooked everything else up correctly.
What happened to this scooter?