that's something I didn't know! the Alpine head unit sends digital signals to the amp? mainly for my curiosity, how/where does it convert to analog/speaker level? Doesn't apply to my 2015 but I'm just very curious. I'm a total car audio geek and I really just gotta know!
On a side note, the work around for me in the past when I couldn't get a wiring diagram for the in dash harness, I'd gotten speaker level signal for the wires leading to each speaker then into the sound processor. Not ideal but got the job done. Assume that would not work in OP's situation since the signal isn't reaching the speakers due to the blown amp.