Described is an electronics system having an individually replaceable electronics module installed therein. The individually replaceable electronics module includes a component, a light-emitting device (LED) disposed near the component, a processor module for performing diagnostics on the component and producing a message based on results of the diagnostics, and a microcontroller in communication with the processor module to receive the message produced by the processor module. The microcontroller determines whether the component is faulting based on the message. A DC power source is coupled to supply power to the microcontroller after the individually replaceable electronics module is electrically disconnected from the electronics system so that the microcontroller can illuminate the LED if the received message indicates that the component is faulting.