Amplifier Options for stock JBL w/Nav

Hi Folks,

We still are cruising around in our 2010 Prius IV, but have been without sound for a few years. It seems there are a few people who've commented here and there on various forums about a random, unbearably loud, squeal, screech, or static noise coming out of the speakers, that could occur even when the audio was off. If I recall correctly, we'd have to pull to the side of the road and turn off the car. The consensus of the forums was that this was likely the amplifier. I pulled the fuse for the amp, and it hasn't happened since.

We have the JBL system with Navigation (DVD-based), backup camera, steering wheel controls. I think this is the E7022 head unit. It's fine for our purposes, and all the functions except sound continue to work. So what would be the simplest way to get sound working again? Do I need to find out exactly what amp is under the passenger seat and replace with the same? Are they made new or would I have to take a chance on used? Is there an aftermarket amp that is pretty much plug and play for this?

I realize that the problem might not be inside the amp, but might be in the wiring who knows where. I doubt my time and ability to track such a thing down, unless there are common failure points to check. I'm hoping a known good replacement amp would not be too expensive for a "try this" method of troubleshooting. I'm open to other suggestions.