MacBook Air won't power on, unless battery disconnected and plugged in

This is for those who have had trouble with all the combined issues: - Macbook Air 2012-2017 ( possibly other models) - Won't turn on unless the battery is disconnected for a short time and then plugged in. - Connecting the mag-safe cord is what only turns it on. - Tried SMC reset Tried PRAM/NVRAM - Tried a different battery - Battery still charges. - Ready to sell it for parts due to a total waste of precious time!