In addition to the good advice you've been given here, make sure it's not the amp that's causing the problem -- they're known to go south, and I have 2 bad ones (3, actually, since I have the same issue in my Sierra).
If you notice that the 'snap crackle & pop' occurs after the vehicle has been sitting in the sun for awhile, or after a few minutes of operation (but not necessarily at startup)... the amp becomes a prime candidate. You can remove one of the rears and test it elsewhere to confirm. Or, you can get what you'd use as rear replacements in a 'new' system, and install them; if you still get 'rice crispies', you know it's the amp at that point (and you're ahead, cost- and time-wise). You don't need to spend a fortune on the rears -- they're there for 'fill', and your main soundstage is in the front. That's where you make the main spend on speakers. Some people don't even run rear door speakers.
In the short-term, you can use your balance / fader to isolate to a 'good' channel(s), until you decide what you want to do. If it *is* the amp, it's an excellent opportunity to just upgrade to a new BT-enabled HU / speakers / (and if you want it, an amp). Get an adapter harness (two main vendor choices, which are discussed on this board in several places), and you'll have a much easier time of it. Also, disconnect (if not outright remove) the Bose amp, so you don't have the needless current drain on the electrical system, going forward.
As far as repair / replace the Bose amp... even *if* you were to find a resource to repair it, the cost is exorbitant, compared to just getting an aftermarket. And the used ones on eBay, etc. (which are also priced fairly high, due to supply / demand) are really just borrowed time -- you don't know how long that new one will last, and when it goes, you're back to square one.