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hey i hope someone can help: i changed the battery on my mbp 2017 15”. did it with the ifixit guide und battery. auto boot has been switched off prior to the repair.i already tried the smc rest and pram reset shortcuts etc. Everything powers on, but the touch bar wont come to life. i have reconnected the touch bar display and digitizer cables carefully. I have never bent them hard during the process, the were otherwise untouched. the contacts look fine, cleaned everything with air. i have redone the whole procedure carefully - it still does not power on. The Touch Bar is not shown in the keyboard menu and there is no Touch Bar process to pkill.. So I guess its not communicating / seems to not be connected even though the cables are connected just fine.. Before exchanging the battery everything worked properly. I changed the battery because it was not holding a charge for more that one or two hours and had been used daily for the past 3,5 years. any ideas how to solve this?
Was your Mac functioning OK except for a weak battery before you replaced it? Can you power the laptop on with the battery disconnected?
I know is an old post but a lot of people including me have this problem. To solve this problem, I tried all sorts of things. knowing that I was very careful when I changed the battery and keyboard, so I ruled out that the problem was a physical one. I knew from the beginning that it was software. So, I discovered that if you watch youtube in full screen mode until the battery is completely discharged and then you charge it, after about 30 minutes you turn it on the MacBook , but it must be plugged in charger, you will have a pleasant surprise , your touchbar has started and will work without any problems.
