Chosen Solution
After replacing the battery on a 13" MBP, my trackpad and keyboard are no longer functions at all. Power button works, but I have no caps lock light on the keyboard on boot or when gets to login screen.I’ve checked I/O cable and all seems to be fine seated correctly.I’ve also noticed the trackpad does’t seem to have any type of click when pressing it, when I know it did before the batttery was replaced. Any give me any advice on what i should do?Replace the I/O cable and poss also the trackpad?
I Often need to replace the MacBook Pro 13" Retina (Early 2015) Trackpad Cable as it tends to be damaged from the grit sitting on the bottom cover and/or the foil wires have become over stressed. If the cable has a short it will also affect the keyboard as well. The power button is a simple circuit which doesn’t involve the internal USB hub the keyboard and trackpad connect to. Using an external keyboard and mouse open up About this Mac > System Report and then jump down to USB section there you can see the two share the same hub.
