Alternator wiring green, purple and yellow

Hi this is Dusty, I'm one of the auto experts on RepairPal's Car Genius team! Uh-oh, that's no good for sure. I peeked at the wiring diagrams for your Altima, and you are correct, the order is purple (pin 2), Yellow (pin 3), Light Blue (could look greener with age, pin 4). If you have any other questions feel free to give us a call at 877-913-1554! We'll be happy to help or find you a certified shop in your area!