I have a 2008 H3 Hummer with the base sound system. Everything was stock and I got speakers and a double din to install. I installed the speakers and they worked with the stock head unit. Then i installed the head unit and it turns on and everything works. I go to play music and i get no sound out of any speakers. I retried wiring and I even directly hooked up a speaker to the HU using other speaker wire and it didn’t work. Any suggestions? I’ve looked online and there is not a stock amp either.