my 99 has the 2nd black plug but i only had 1 pink wire coming from it. i cut off the plug and tossed it so 4 yrs later when i went back to stock, i had no idea where to plug the pink wire into the factory hu. the junkyard car i found had the black plug but also had 3 more wires in it. that i did not use since the 3 wires were in the main harness on my car. i just compared the color scheme and figured it out. my hu has hi/lo equilizer. not the 5 band style some hu have. maybe that is why wires on black plug are different? or maybe the wiring got tweaked from 99-00-01-02
