Very likely to be the fuse and very likely that it will be broken rather than blown. Due to the tremendous current that passes through it, the fuse heats up and expands. It does this during every glow cycle and then contracts after cooling. This cycle fatigues the metal and a crack forms. Eventually it separates.
Replacement is all that is necessary as it takes years for this to reoccur.
Bosch Master, ASE Master, L1
33 years MB technician