So I was getting engine noise, checked grounds, cables, etc. Turns out it's something to do with the harness. If I jiggle it just right almost all the noise goes away. I read something about the RCAs having some kind of inline fuse that causes that when it goes. I'm not really looking forward to spending $50 on a RCA harness either. Is there an alternative?

Are you sure no wires have been rubbed bare on something metal?

No, from what I can tell everything looks in order. The harness itself, although used, appears to be in decent condition but I've definitely narrowed my problem down to the harness itself. Both ebay and Pioneer want $50 for the RCA harness and to be honest it's a piece of shit so I was wondering if there was an aftermarket alternative or if someone had a DIY success story on fabricating one themselves.