The activation signal for the brake lights leaves the N.A. contact for switch I30 which receives an ignition-controlled power supply by means of the connection between the ignition switch H01 (INT) and pin 11 connector E of the junction unit under the dashboard B02.The line is protected by fuse F37 inside the actual control unit (B02).When the brake pedal I30 is pressed the N.A. contact for the switch closes and the centre rear light F40 is supplied via pin 5 connector D of the junction unit under the dashboard B02.At the same time a signal is sent to the body computer M01 which lights up the side brake lights in the rear light clusters F30 and F31 from pins 32 and 22 of connector A respectively.The body computer may be supplied via pin 11 connector E (ignition-controlled supply) and pin A connector C (direct supply) of the junction unit B02.There is a proective fuse F1 for the direct power supply located in the junction unit B01.On versions with the Comfort instrument panel, if there is a failure in the circuit or the bulbs, the Body Computer notifies the instrument panel (pins 9 and 8 of connector A), via the CAN line (pins 5 and 6 of connector I) and the "exterior lights failure" warning light is switched on as well as all the available messages on the display.Pins 8 and 9 of connector D of the body computer are earthed.