I guess the reason you clicked this question is that you thought it was the backlight issue but it is not. This problem puzzles me.
ISSUE: My display does not work.
What MacBook do I have?
Model: MacBook Pro (15-inch, Late 2011)
CPU speed: 2.2 GHz
CPU Type: Intel Core i7 (Sandy Bridge)
CPU Model: 2675QM
Bus Speed: 1333 Mhz
Turbo Boost: Up to 3.3 GHz [Never manually boosted it]
Installed RAM: 8 GB (2x4GB)
RAM Type: PC3-10600 DDR3
Hard Drive: 1TB Seagate Baracuda
Display Size: 15.4-inch
Graphics Card: AMD Radeon HD 6750M and Intel HD Graphics 3000
Card Memory: 512 MB (AMD) and 384 MB (intel, shared)
Issues in my MacBook
- GPU Failure like most of the MacBooks from this era.
- Speaker doesn't work as I had posted a question about this before so cannot say if the chime is coming or not.
- The backlight is doesn't seem to be the issue cause I've tried to put light through the Apple logo.
- I've bypassed the GPU by an NVRAM tweak but when this issue started I've mistakenly reset the NVRAM so the computer won't boot to macOS.
- Both the fans spin.
- The CD Drive make the usual noise.
- Since I removed the NVRAM tweak to bypass the GPU now I can't see the apple logo to verify the backlight test so I connected few Bootable pen drives and started Internet Recovery to see the Drive icon and Spinning Globe.
- Tried Verbose Mode to see text for testing the Backlight and as always, no a luck
- Opened up the back and removed the display connector and reinserted it and… you guessed it not luck.
With these obstacles, I can't really tell what is making this display issue. I really hoped I could give a bounty but my reputation is quite low but still, I really lost hope in this computer and as a student, I don't think I can fix this computer ever again.