I’ve decided to take the lazy route & see if anybody else has encountered this problem before I do a deep dive myself. I’ve owned my car for about 5 years now so I don’t remember the specifics, but the previous owner hadn’t done any modifications to anything to my knowledge. I installed a head unit about 1 to 1.5 years in & I’m pretty sure the audio was slightly more consistent at that point in time but it now only works rarely at best. I couldn’t pinpoint the last time I heard audio but it was within the last couple of months. When it does come on, it’s usually when I’ve been driving for a but at that point. All original hose speakers, pretty positive all of the wiring is done properly (professionally installed (so who knows actually)), onto a second head unit since the first one & still the same problem, & I’m just not exactly sure what could be wrong. Had some people look at it, they said it was fine. Checked all of the fuses, they were fine. Any help that isn’t just “replace the entire speaker system & rip out all of the bose nonsense” would be appreciated as I’ve seen that before as a solution (unless that’s genuinely what it might be). Thanks for any help anybody gives ahead of time.

 

It sounds like you're running an aftermarket head unit with OEM Bose speakers. If so, did you install a sound processor module like the PAC ROEM-NIS2? It may be something as simple as adjusting the level outputs on that. Another possibility is that the OEM Bose amplifiers are not functioning properly. They may not be turning on at all (due to a power, grounding, relay, etc.) issue. The amplifier that powers the subwoofer is notorious for having a faulty relay which causes it to not turn on. It's fairly simple fix if you have a soldering iron.

Even though it was professionally installed, some of these "professionals" don't really know what they're doing.

As far as a first step, I would verify the Bose amplifiers are powering on. You should hear a faint 'click' from the relay when they power up.