E2021 Stop light

Description

The brake lights are located at the rear in the side lights and in the central third brake light and consist of 10 separate bulbs.

These are operated whenever the brake pedal is pressed, by means of a switch on the pedal itself.

Note

the switch fitted on the pedal assembly consists of two contacts which supply two signals: the first which is the 'N.A.' type recognizes the position of the brake pedal when it differs from the rest position; the second, which is the 'N.C.' type, recognizes the brake pedal in the rest position.

The switching on of the brake lights is managed by the Body Computer.

The control function is activated by the go ahead signals from the key in the ON position (INT) and the contact for the above mentioned switch.

The 'N.A.' switch information is sent via the CAN, in particular to the engine management control unit and the ABS control unit. Wiring diagram E5030 PETROL ENGINES ELECTRONIC CONTROL Wiring diagram E7020 ABS .

The correct operation of the lights is controlled by the brake lights 'check' function: the following are checked:

• open circuit (bulb missing or wiring broken) which can be diagnosed without a command
• short circuit to earth (bulb short circuit or wiring short circuit to earth)
• short circuit to Vbatt (wiring short circuit to Vbatt)

The continuity of the fuse protecting the bulbs is also checked.

If one of the situations described above is detected, the Body Computer notifies the CAN of the failure state: a special 'lights failure' warning light comes on in the instrument panel and, at the same time, the information is shown on the display.

Description of operation

The supply for the switch I30 is controlled by the ignition (INT) from the line for fuse F37 of the underdashboard control unit B2: when the brake pedal is pressed, the switch closes and sends the 'N.A.' signal to the Body Computer M1, pin 2 of connector F.

The 'ignition ON' signal (INT) for the switch H1 reaches the underdashboard control unit B2 at pin 11 of connector H and from there moves on to the Body Computer M1 (pin 9 of connector F).

The Body Computer M1 controls the supply for the brake lights in the light clusters F30 (left) F31 (right) from pins 32 and 33 of connector E.

The Body Computer M1 is connected, via the CAN line, to the instrument panel E50, to manage the 'lights failure' warning light if there are failures detected in the circuit.

The switch I30 directly controls the centre rear light cluster F40 via the underdashboard control unit B2, pin 5 of connector D

Wiring diagram

Components

Component location