I recall comments here about this being particularly sensitive. I had an issue with no iSight on rebuild, however taking to bits again and seating and reseating this connector a few times resulted in the iSight camera working again (phew).
Installed a 2019 SSD in my late 2015 iMac retina, purchased from fast_macs on eBay AOK with nearly 1900MB/s write 1800MB/s read (ish). Also installed Apple 2TB drive too whilst I was doing it.
Can anyone confirm that the mic is the middle small hole as the photo in step 14 appears to show a larger hole? I ask as I don’t have the mic kit and will have to cut the kit to suit my late 2015 iMac 27 retina. Thanks.