instalation help

  1. S

    I can only get sound out of 2 speakers with a 4 channel amp

    I just finished installing a 4 channel amp into my car and I can only get 2 channels to work. I have a skar audio RP-75.4AB 500w amp, and a pioneer s322bt head unit. In addition to that i have a 2 channel amp running a sub. I have been using the head unit to power the 4 door speakers but it did...