An optical communication probe enables a diagnostic tool to optically communicate with an external device, such as an appliance, through a low intensity indicator light of the external device. The communication probe is powered by a battery that is selectively coupled to the communication probe through a switch. The switch is coupled to a diagnostic tool to receive a power status signal from the diagnostic tool. In response to the power status signal indicating user inactivity at the diagnostic tool, the switch de-couples the battery from the communication probe to conserve battery life.