I’m having issues with my radio and not sure what’s going on. I’ve had an aftermarket head unit and subs in the rear for as long as I’ve had the truck, up until last week all was well. It’s now developed a static sound that sounds almost identical to if the speakers were blown, which they’re not. I’ve checked all grounds, even went a bought a new head unit, same issue. Swapped for different speakers nothing seems to change it. Someone mentioned a noise filter mounted on the fender near the fuse box but I’m not quite sure what I’m looking for or what it even looks like. All help would be appreciated.

 

toyota 90980-04041
it's a small black square that's bolted bolted down around down coil