battery replacement creates "over temp" error.

I replaced my battery because it was bulging and had lifted my display. Prior to replacement the phone worked perfectly. After replacement the phone powers up but screen displays "Temperature. IPhone needs to cool down. " swiping to activate the phone yields a blank screen with the usual header showing reception, battery, etc.

I have tried reseating the battery, fully charging, chilling, none of these have had an affect. The phone is not addressable via usb long enough to reinstall software.

One concept that may play a role here is that the old battery was stuck to the logic board due to expansion and heat. I teased it apart carefully but maybe a component was lifted. Does anyone know where these phones sense temperature?