Chosen Solution
I bought my daughter this new MacBook Air. But within 2 months at college she spilled part of a glass of water into the keyboard. It was not plugged into AC power, just on battery at the time. She said the laptop shut off immediately. She quickly inverted the laptop and tried drying off any moisture with a towel. She called me and I told her not to try to power anything up. She brought it home and I rigged up a fan to blow on the underside of the open laptop for 48 hours. I plugged it in and it powered up fine, operated fine, and the only problem I noticed was if the AC cord was removed it would shut off immediately! She was in the middle of finals and needed her notes so she took the laptop back to school for a few days until the semester ended. I decided to order in a new battery and a IFIXIT tool kit (fantastic) to replace a possible shorted battery in the mean time. She took it to the Apple store because it was still under warranty but the store told her there had been water damage and the laptop had to be replaced at her expense! So I took the battery out and tried cleaning up what seemed like corrosion around a few components with alcohol and swabs. I tried again to boot up on the new battery and nothing happened but the charging light on the MagSafe connector came on. No screen, but the keyboard lit up. I did a forced shut off and began a total teardown of the motherboard/logic board, I/O etc to eliminated corrosion or deposits in as many removable assemblies as possible. I put everything back together after cleaning it all topside and bottom side of each. Powered it up and everything came to life and the new battery indicated 98% but finished charging to 100%. The only problem is it will not use the battery for power. It has to remain on AC plugged in to work. I did use CoconutBattery health app and it indicated a fully charged brand new battery with no cycles yet. Can anyone tell me what component may be the culprit here? Thanks
Watch this video from Louis Rossmann see if it helps: Macbook logic board recognizes battery but won’t run off of the battery
