Hey guys. New to the forum. I use to install back in the day. Now that I’m 44 I try to not install anything. My 19 year old has a 2012 GMC Sierra 1500. We put new speakers in it, added a backup camera, Bluetooth , xm, etc. everything works fine but the amp. It’s a JP8 from down4sound. We are trying to run 2-12” comp rt’s. The subs are 2ohm dvc. I have each sub wired in series for a 4 ohm load and then paralleled . The amp is mono but has 2 speaker inputs. It’s frustrating because I’ve checked voltage, the subs, wiring . Checked to make sure the pre out is on in the radio. Please help. Am I missing something obvious??