Chosen Solution
I’ve just replaced the thermal paste of my 5 year old MacBook Pro because it was running at over 85 degrees celsius when doing normal work. I dediced to follow the instructions and disconnect the battery before doing this but now the battery is not recognised anymore and I can’t power on or use the MacBook without a power connector. For some reason I can see all information regarding the battery in the OS e.g. temperatures, cycle count, manufactures etc. but can’t use the battery. SMC and PRAM resets have been done as well. Is it possible I damaged the battery Interposer and that’s why it won’t work anymore? This step shows it: MacBook Pro 13" Retina Display Late 2012 Heat Sink Replacement I’ve accidently made some small scratches on the on the logicboard when removing the Interposer, it doesn’t look deep or something like that but maybe it’s too much. Did I break it and should I order a new Interposer or did I break the connectors on the logic board (although it doesn’t look fragile)
Coconut battery shows Battery failure Yes en macOS battery status poor
Examine your board where the heat sink ends are crimped and look for an oily type of residue. If you find it, your heat sink liquid has leaked and you will need to replace it. MacBook Pro 13" Retina Display Late 2012 Heat Sink Replacement
