Abstract: This is a method of controlling an electric heater of a catalytic converter. An electric heater is powered by two separate batteries. There are an electronic control unit, a power switch, and an isolating switch providing logic control to the electric heater.

Abstract: In the case of an electrical wiring for a motor vehicle having a primary system which includes a voltage-controlled generator, a primary energy accumulator as well as at least one primary energy consuming device, and having a paralleled secondary system which includes a secondary energy accumulator as well as at least one secondary energy consuming device, the secondary system includes a control unit with a controllable resistor connected to the generator. The control unit monitors the charge condition of the secondary energy accumulator. As a function of the currently determined charge condition of the secondary energy accumulator, the control unit, on the one hand, controls the controllable resistor in such a manner that, during the charging of the secondary energy accumulator, the primary system is not overloaded.