First of all Welcome to the forum Jearmold82! Try this remove the loc, then play the music see if it will turn all the way up. If it does you might have a bad LOC or you might need a different kind of LOC that uses independent power supply.
I have done this previously it does operate fine without the loc but it also operates fine if I turn my amp gain down it just doesn’t operate well after a few minutes of really loud bass kind of wondering if there is a factory amp in this car if so maybe I should pick my input up on speaker wires coming out of factory head unit instead of right before it goes into the speakersFirst of all Welcome to the forum Jearmold82! Try this remove the loc, then play the music see if it will turn all the way up. If it does you might have a bad LOC or you might need a different kind of LOC that uses independent power supply.
Because my car, IS the most basic model(5MT, electric windows & locks as extras) and has the AM/FM/USB radio, with full range speakers ...why would you ad an amp the system has loud bass anyway they use rockfordfosgate subs in the door panels and the stock system is more than adiquate