323000090 - E2021 BRAKE LIGHTS - DESCRIPTION

DESCRIPTION

The vehicle brake lights are located in the rear light clusters (in the form of a red bulb) and in the special central third brake light, made up of 4 separate bulbs.They are operated each time the brake pedal is pressed via the special switch on the pedal.

The switch fitted on the pedal unit consists of two contacts which supply two signals: the first is the N.O. type, which recognizes the position of the brake pedal if it is not in the rest postion, i.e. the pedal is pressed; the second is the N.C. type, which recognizes the position of the brake pedal in the rest position.The lights are turned on by the N.O. contact (pedal pressed).

The control function is activated by the enablement signals (key in ON position) and the command from the switch contact mentioned above.The brake light check function monitors that the side lights are operating correctly: the following are checked:- open circuit (bulb missing or wiring interrupted)- short-circuit to earth (bulb s.c. or wiring s.c. to earth)- short circuit to battery voltage (wiring short circuited to Vbatt)The continuity of the fuse protecting the switch on the brake pedal is also checked.When one of the situations described above is ascertained, the Body Computer makes the failure status available to the CAN: a special lights failure warning light comes on in the instrument panel and, at the same time, the information is shown in the display by means of the specific symbol.