Macbook Air bluetooth fails to connect already paired devices after screen is replaced

Have an authorized service technician check your handiwork. That is not an officially serviceable part for consumers.

iFixit might give you some guidelines, but remember any access by end users may be frowned upon if an official repair tech was asked to do warranty work. We can't guess Apple's policy on this board, and can only share with you our experience in the matter. Yours may differ.

If you are part of the self service repair program, I would contact their adminsitrator for direction, as not all of us have their blessing.