Description Of Operation: Notes

Fig 1: Identifying Communication Flow - Dipped Beam

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 2: Identifying Dipped Beam Circuit Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Dipped beam is on when the light switch is in position 2 and the ignition is in position OFF, ON or START. When the ignition is on, the power supply to the dipped beam lamps is controlled by DICE. Dipped beam is used as daylight driving lights on certain markets (light switch in position 0 or 1).

So that DICE can safely determine in which position the switch (10) is, (0-1-2), the control module uses information from TWICE and its own pin connection.

The parking lights are controlled by TWICE which gives information to the bus (ON/OFF). The message ON corresponds to switch position 1 and the message OFF corresponds to switch positions 1 or 2.

To determine which position the switch is in, DICE uses its own pin connections. DICE pin 39 is connected to switch pin 5, which corresponds to position 0. DICE pin 15 is connected to switch pin 4, which corresponds to position 2.

From pin 4 on the light switch (10), voltage +X is fed from the ignition switch to pin 15 on the control module. This causes the main lighting relay to be grounded via pin 4 on the control module and the relay closes. Voltage +30 is fed through the relay via the filament monitor to the fuses (7 and 9).