With the pressure increasing to develop cost-effective zero-emission vehicles, manufacturers who are developing electric automobiles are faced with a double-edged problem: how to develop new, lighter weight electronics systems, necessary for increasing vehicle efficiency and range, which will operate in the harsh, electromagnetic interference (EMI)-intensive environment inherent in vehicles with electric drive systems. One promising technology for these new electric vehicle electronic systems is the serial multiplex communication networks now beginning to be used for networking electronic components and modules in traditional internal combustion-type vehicles.The use of serial communication technology can provide system designers with a variety of benefits. Serial networks can help reduce the size and complexity of the vehicle's wiring harness, thereby reducing the vehicle's weight and cost to manufacture. In addition, these networks can also provide the means for adding enhanced features to a vehicle which are not currently available, allowing designers to differentiate their products from vehicles with more traditional feature sets.As existing in-vehicle serial communication protocols such as SAE Standard J1850 and the Controller Area Network (CAN) begin to appear in production vehicles, this raises an important question: will current serial communication technology, developed for gasoline-powered vehicles, operate properly in electric vehicle applications?As the in-vehicle communication technology, at the device and component level, gets faster and more complex, EMI is becoming a greater concern in current applications. The electric vehicle can be a significantly more difficult environment than an internal combustion vehicle in which to achieve and maintain error-free operation.This paper describes a project in which existing automotive multiplex devices were used to construct and operate a serial multiplex communication network in an electric vehicle. System technology and construction will be discussed, as will the effects of EMI on communication in the electric vehicle and the problems overcome to achieve and maintain reliable network operation.