No backlight after SMC reset, after botched battery install
Ello! My 2015 MBP 15" had a dead battery. I replaced it, but accidentally plugged it in before I connected the trackpad cable, and I made the trackpad chip smoke. It booted up fine after that, but trackpad and keyboard didn't work (display still worked at this point, and worked for several reboots). I installed a new trackpad (correctly this time), did an SMC reset, and now it boots up, trackpad and keyboard work and light up, but the display has no backlight. I confirmed with the "flashlight thru the apple" test.
Sooo, I checked all the cables, cleaned them off with 99% ISO, reseated, didn't help. Yes, I also did the cable inside the display too (where it connects under the WiFi antenna). Didn't help.
My backlight fuse looks fine. I'm getting continuity on both sides the fuse, and I'm getting 10 volts on both sides the fuse with the battery plugged in. It does not appear the fuse is shorted to ground, either.
What's next? Replace the display cable? Replace the backlight driver chip? I'm at a loss here.