Hi @AnniePRICE22 it's entirely possible the heat from the radiator has hurt the Fitbit. Have you tried doing a restart of it?
Best Answer@AnniePRICE22 here are the directions - click to go there. Let us know if that helped.
@AnniePRICE22 great news! Glad you were able to get it going again. If you'd like to explore the forums, check out the link in my signature.