A method of configuring an aircraft electrical system. The aircraft electrical system comprises a wiring harness and a plurality of electronic modules. The wiring harness comprises a plurality of connection points. The method comprises: connecting a first electronic module in the plurality to the wiring harness via a first connection point in the plurality; transmitting by the first electronic module, a connection point identification request; in response to the transmitting, receiving at the first electronic module from the wiring harness, an identifier of the first connection point; on the basis of the received identifier, determining configuration data for the first electronic module, the configuration data being associated with the first connection point; and configuring the first electronic module to operate in accordance with the determined configuration data.