Chosen Solution
I’m a bit panicked, this was my first time doing a repair by myself and I followed the instructions on this site what I would like to think was perfectly. I replaced the battery and now the charger isn’t lighting up to signify it’s charging but also when I hit the power button the screen doesn’t even light up to say that the laptop needs to be charged or is charging. If there’s anything I might have done wrong or should check for please let me know? I need all the help I can get!
From what you are describing it sounds like the MagSafe board is not connected and/or needs replacing MacBook Pro 15" Retina Display Mid 2014 MagSafe DC-In Board Replacement and/or the MacBook Pro 15" Retina Display Mid 2014 I/O Board Replacement as the connection to the logic board is through it.
