So I installed an Alpine 12" type S sub and a 1250W Soundstream mono amp in my 5th Gen.
I've got an interesting yet troubling problem I've yet to figure out.
I have what sounds like a ground loop of some sort going on however, when I roll either the drivers window or passenger window down about half way the engine hum noise goes away.
I can eliminate the noise by opening either front door as well.
I have verified multiple times all my ground connections and made them as short as possible at the amp.
I've also tried a couple different ground loop isolators with no effect.
New cabling no change.
I guess my next move is trying a different location to pull ACC line voltage for the remote turn on to my amp.
I removed the remote turn on to the LOC to see if that would help because it can trigger ON automatically when it receives and input.
I know audio wiring issues can be a PITA but I'm open to suggestions!