I have a 1993 Infiniti J30 with a JVC KD‑R330 HU. On the back of the HU are 2 rca outputs, a white and a red. My car came with bose 6x9's that had built in amps, so the plugin for the rear 6x9 speakers had 4 wires going to it, two black, one white, and one white with purple stripe.
So I tested...