That step 12 gave me a hard attack. I had not read properly and I thought that the cable for the light ambient was just coming off like the other three connectors to disconnect. When I was left with the bare cable without the connector at the end, I #!?*@*! a bit but then realized that it was a lift tab that which, when pushed down, put the pressure of on the cable to stay in place. So all was fine, I was able to replace the left fan (had to replace the right fan about a year ago). The ambient light cable was fine as the keyboard glowed properly.