I've just replaced the battery on my MacBook and had this issue. I hadn't spotted the clip on the ribbon connector so I lifted it and re-inserted the ribbon, the keyboard has started working now but the trackpad is still unresponsive. I've ordered a new ribbon to see if that fixes it. If that doesn't work I'm guessing it's a new trackpad?
=== Update (02/16/2022) ===
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This is frustrating.. I've got a new ribbon from an Amazon seller and after installing it the trackpad now works but the keyboard doesn't.. It's got to be the ribbon right? Switching back to the old ribbon and the trackpad doesn't work and the keyboard does.. It looks to me like another faulty ribbon right? Something weird with power delivery on the trackpad controller perhaps? I've asked seller - maybe they'll send me another ribbon for free.
I've just replaced the battery on my MacBook and had this issue. I hadn't spotted the clip on the ribbon connector so I lifted it and re-inserted the ribbon, the keyboard has started working now but the trackpad is still unresponsive. I've ordered a new ribbon to see if that fixes it. If that doesn't work I'm guessing it's a new trackpad?
=== Update (02/16/2022) ===
This is frustrating.. I've got a new ribbon from an Amazon seller and after installing it the trackpad now works but the keyboard doesn't.. It's got to be the ribbon right? Switching back to the old ribbon and the trackpad doesn't work and the keyboard does.. It looks to me like another faulty ribbon right? Something weird with power delivery on the trackpad controller perhaps? I've asked seller - maybe they'll send me another ribbon for free.