I'm attempting my very first install and need some wiring help, please! I have a Pioneer 2500 HU and am using a wiring harness for my GMC Sierra. Got all of the wire harness wires connected to the HU just fine. But the red switched power wire from the HU is not wired into the harness, it goes somewhere else. I am not sure where it goes to tap into the ignition power - maybe the fuse box? I've replaced fuses, but no other experience with the fuse box. So, I'm not sure how to attach the wire, (which has a square ending with a hole in it), if it attaches there - or somewhere else. Thanks in advance for taking the time to help an admitted newsbie.