Chosen Solution
Firstly I know this topic comes up a lot in the forum but none of the solutions have made any difference and this seems slightly different from the rest - MBA Early 2015 model 13” - Previously running High Sierra when issue happened. As part of process - did an inplace upgrade to Catalina - no difference! Symptoms: Went to turn it on one day and just kept chiming for the reboot and looping Let battery go flat and reconnected power and it started up - However internal keyboard and trackpad not working at all. When I connected USB keyboard and mouse I was able to log in and noticed Bluetooth also no longer exists in Sys Prefs and can not enable it through Network - Bluetooth PAN, Also “no trackpad found “ in Sys Prefs but WiFi still works. On checking System Information/System Report - no bluetooth information there and also noticed under USB - it is missing the internal memory card reader and Bluetooth USB Host controller No drop or water damage Actions to try and resolve (with no success) Opened it up and noticed bad swelling on the 2nd battery cell from the right - (of particular note this was an IFIXIT replacement battery !!!!!) Replaced battery and re-sat all trackpad and keyboard cables - no differenceRemoved bluetooth/airport card and re-sat - no differenceReset SMC - Shift+control+option+power on internal keyboard for 10secs which caused MagSafe light to flick from amber to green - no difference other than some confirmation that internal keyboard inputs being read/received (however internal keyboard does not seem to work to enter recovery mode (command-r) or NVRAM/PRAM reset - this can only be done via USB keyboard - all done - no differenceSwapped out cable trackpad to board from working MacBook Air - no differenceSwapped out whole trackpad from working MacBook Air - no differenceEven put all the old trackpad and cable into the donor device and all worked in that OK, I’m all out of ideas - I haven’t replaced the keyboard but my suspicions lie with USB bus issues but both USB ports work OK ??????? Just seems a big coincidence that the battery cell over the trackpad was the one that had a large swell in it and now they don’t work at all Any help greatly appreciated Update (01/13/2021)
As you say Dan - looking at the schematic - this explains why keyboard/trackpad/card reader and Bluetooth are all not working. Will swap out trackpad and cable once more to double check
Sadly a swollen battery can create a lot of issues! So you do need to address the battery replacing it MacBook Air 13" Early 2015 Battery Replacement But diving deeper into why you have issues with your internal keyboard and trackpad (also called a touchpad) gets into what was underneath the battery! The trackpad!! Unlike the older models Apple leveraged the trackpad as a junction point for the keyboard as well as the USB2 hub that both the keyboard and trackpad connect to and the USB signals and power trade to the main logic board over a single cable. So you can have a damaged trackpad or the trackpad cable has been damaged to the signals aren’t getting through! I would first try a new cable MacBook Air 13" (Mid 2013-2017) Trackpad Cable to see if that fixed things otherwise you’ll need a new MacBook Air 13" (Mid 2013-2017) Trackpad As for your Bluetooth issue I would wait until you have the internal keyboard and trackpad fixed first as its possible the lines are shorted messing up the PCH USB port connections. Update (01/13/2021) Here’s a view the of schematic
