Sleep/hall/display sensor location

Hi everyone, I have mid 2015 15" MacBook Pro (A1398) which doesn't go to sleep when the lid is closed (display not turning off as well). Googling this problem led me to conclusion that this is a hall sensor problem but I was unable to find the answer where it is located on this model (probably should be two sensors as well?) to probably check it for corrosion/cleaning or to understand if any part can be changed. I found somewhere that display sensor located on trackpad or trackpad cable?

Also this is clearly not a software problem as I have done all normal stuff like checking apps that prevent sleep, smc reset, full clean install and etc.

Paper clip, magnets play also didn't gave any results at all.

Please let me know if you know where this sensors are located on this machine or maybe if anyone have any other insight on this problem?

Thanks and have a wonderful day everyone!