The DSC3 has two indicator lamps. These are
These two indicator lamps serve the purpose of indicating system statuses and system faults of the DSC3 in the instrument cluster.
When the ignition is switched on (terminal 15) the two indicator lamps are activated and their function checked. The two indicator lamps go out after approx. two seconds if no faults are found in the control unit self-test.
The safety lamp is off when the ABS is in standby mode. If the control unit detects a fault in the ABS system which leads to deactivation of the ABS, the ABS safety lamp lights up thus signaling failure of the system.
Activation of the safety lamp has been changed compared to the previous ABS systems:
The ABS safety lamp is connected to the 12 Volt supply via terminal 15. If the ABS is fully operable, the control unit applies high level at pin 32. This status is recognized by the electronic circuitry in the instrument cluster and the safety lamp is not switched to ground.
If there is a fault in the ABS system which results in its deactivation, the control unit switches the high level to low level.
This status initiates the instrument cluster electronics to switch ground through to the safety lamp so that it lights.
The same status as for an ABS fault is assumed automatically if the control unit is not connected.
The advantage of this new method of activation is that it renders the spring contacts in the plug connector or the intricate jumper circuit via the valve relay unnecessary.
The lamp is off when the DSC3 is fully operable, it flashes during a DSC or ASC control procedure.
The lamp lights continuously if a fault is found in the DSC3 system or if the system is temporarily deactivated by means of the DSC passive button.
The multifunction lamp receives its 12 V supply via terminal 15 and, depending on the relevant functions, receives clocked or continuous ground from the control unit.
The multifunction lamp receives ground via a spring contact in the plug connector in order to draw the driver's attention to failure of the DSC3 even when the control unit is not connected. This contact is open when the control unit is connected.
Note
During diagnosis (= communication with DIS) both indicator lamps light irrespective of whether there is a system fault or not.