SOS switch, component description - GF82.95-P-3210SXU

MODEL 221.0/1 with CODE (494) USA version up to Model Year 8

MODEL 221.0/1 with CODE (389) Mobile phone preinstallation with universal interface, USA/Canada up to Model Year 8

MODEL 216.3 with CODE (494) USA version up to Model Year 8

Illustrated on model 221

Fig 1: Identifying SOS Pushbutton Switch - Illustrated On Model 221

Courtesy of MERCEDES-BENZ USA

Location

The SOS pushbutton switch is integrated in the overhead control panel control unit (N70).

Task

The following are the primary tasks of the SOS pushbutton switch:

Actuation of a manual Telematic Alarm Identification on Demand (emergency call system) (TELE AID) emergency call
Visual feedback signal of the TELE AID operating conditions in the event of a manual as well as an automatic emergency call

Design

The SOS pushbutton switch is designed primarily as follows:

Switch contact
A control resistor in parallel to the switch contact
Cap with inscription "SOS"
Integrated light-emitting diodes (LED) for night illumination (circuit 58d) and to indicate operating condition

Function

In the park position, electric current flows through the control resistor installed in the SOS pushbutton switch (parallel to switch contact). When current is flowing through the resistor, the emergency call system control unit (N123/4) knows that the voltage supply line and the ground line are functioning properly. When pressing the SOS pushbutton switch, the control resistor is bridged by a switch contact. The SOS pushbutton switch is read in by the emergency call system control unit over a discreet line. When the SOS button is pressed, a manual emergency call is recognized by the emergency call system control unit and then transmitted.