A hearing instrument comprises an openable cover lid, the cover lid comprising at least one electrical input element and at least one lid contact terminal arranged to physically and electrically contact at least one corresponding device contact terminal when the lid is in a closed position. The cover lid further comprises at least two electrical input, each of the at least two input elements being functionally associated with the impedance between the lid contact terminal and a further terminal, and the hearing instrument comprises means to infer the state of the input elements from said impedance. In a preferred embodiment, the number of input elements is equal to or larger than the number of lid contact terminals. In a further embodiment, the lid is the lid of a battery compartment of the hearing instrument, and in a closed position of the lid at least one of the input elements is in electrical contact with one of the terminals of a battery lying in the battery compartment.