Abstract: An aftermarket steering wheel control includes a housing that includes a user-operable switch and a control module. The control module is configured to determine whether the user-operable switch has been operated, generate a data frame corresponding to a control signal for operating a vehicle component, and transmit the data frame to a receiver of a control signal interface. Another aftermarket steering wheel control includes a housing with a user-operable switch and a circuit with an output line. The output line is connected to the switch and further connected to a control signal interface. Operation of the user-operable switch changes a resistance on the at least one output line, and the control signal interface is configured to convert the resistance to a control signal for operating a vehicle component.

Abstract: A method for automatically detecting a control signal configuration of a vehicle component includes making a connection to a channel of the component, performing an electrical measurement on the channel, and identifying a control signal configuration based upon the measurement. A method for sending control signals from one vehicle component to another includes making a connection on a channel of one component, making a connection to a channel of the other component, performing electrical measurements on the channels, identifying control signal configurations based upon the measurements, and configuring a control signal interface. A control signal interface includes an input unit, a signal processing unit, and an output unit. The input and output units each can connect to a channel of a vehicle component and perform an electrical measurement. The signal processing unit can determine control commands based upon control signals.