Car amplifier install issue

i have a Genesis Profile Sub car amp running my subs only the rca, power, remote, and earth cables are connected no subs yet..

then i have a genesis profile four channel car amplifier i have all the speakers connected and rca's i get no power light come on at all.......there is a 20 amp fuse plugged in the amp the user guide online states that the car requires a 30 amp fuse would this be a cause