Polarity

nice dealer. generally, red is positive and white is ground.

 

or use volt meter

 

Or wiring diagram.

I've found white-with-a-black-stripe to be a widely-used ground color in Prii. (Still no substitute for checking the particular circuit you're looking at, with a voltmeter, or the diagram.)

Uncover any of the ground points in the Prius, and you'll see scads of white-with-black-stripe wires attaching to it.

-Chap

 

Red is usually +positive, white and black are ground.