The present invention discloses embodiments of an apparatus, system and related method for diagnosing initiators in air bag systems. An embodiment of the system comprises a diagnostic circuit electrically connected between acceleration switches and one or more squib, that is user-activated via a momentary switch, and with user-feedback, wherein a user can diagnose the health of the one or more squib with no power drain while inactive. An embodiment of a method related to the system comprises activating a momentary switch, completing a circuit whereby a diagnostic circuit may function, indicating to the user that the diagnostic circuit is functioning, regulating the current into the diagnostic circuit so that the squib does not fire, boosting the signal to a window comparator, detecting the desired voltage by the window comparator, giving feedback to the user that the voltage is good, too high, or too low. An apparatus embodiment of the present invention may comprise an electronics control module for sensing a crash event and initiating an inflation sequence for one or more airbags with an integrated system for diagnosing one or more initiators. The apparatus may include a housing enclosing one or more circuit boards, to which may be electrically connected one or more wire harnesses which themselves are electrically connected to one or more squibs.