You never know if not present to figure out. So we begin to trouble shoot and rule things out.Its possible that you may have placed a negative wire up to a poss. wire on the HU,or you have a bad speaker as well.That would be my next step. Pull the HU out and remove the wires from that and check the ohm load on each speaker and if good rewire there.Alot easier than pulling the door panels againJust unplugged them, no change.