Abstract: The architecture of an automotive wiring, power distribution and accessory control system is described. The system comprises semi-custom two-tier nodes which are distributed in locations around the vehicle to service load devices associated with or found in different regions of the automobile topology. A multiplexed control network interconnects the nodes along with a two-wire bus. Each node consists of a first common board carrying a microcontroller and a basic number of FET driver switches associated with a basic level of accessorization for that region of the vehicle. Each node further comprises a second larger pass through board which supports the first common board in spaced parallel relationship therewith and which carries terminal connectors. The larger pass through board has vacant locations for the addition of FET drivers needed for higher levels of accessorization. These locations are preconnected to the microcontroller but are unused in vehicles with lower levels of accessorization.