Description Of Operation

WARNING: This page is about a different car, the 2001 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying Communication Flow - Main Beam

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Main beam is activated by pressing the dipswitch on the steering column when the light switch is in position 2 and the ignition is in the position ON (+15 and +54). DICE activates the main beam relay.

So that DICE can safely determine in which position (0-1-2) the switch (10) is, it 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.

DICE pin 39 is connected to switch pin 2, which corresponds to position 0. DICE pin 15 is connected to switch pin 4, which corresponds to position 2.

From terminal 4 on the light switch (10), voltage +B is fed to pin 15 on the control module. When switch pin 6 (215) feeds DICE pin 41, pin 11 on the control module grounds pin 5 on the main/dipped lamp relay (8) and DICE turns the main beams on. When the relay has closed, the +30 voltage is fed through the relay via the filament monitor (228b) on to fuse 9 (RH main beam) and fuse 8 (LH main beam).

MIU (540) is powered from fuse 8 so that a lamp 47g on the MIU lights up to indicate that the main beams are on.