Electric heater for a motor vehicle has parallel groups of heating elements with on off switches and control and a monitor for short circuits or circuit breaks

摘要

An electric heater (10) for a motor vehicle comprises parallel groups of heating elements with selective on/off switches (16), a switch control, a total current measurer (26) and a monitor for short circuits or circuit breaks which determines the current difference when each element is by-passed and compares with threshold values.