Emergency call system button, component description - GF82.95-P-4400CWU

MODEL 204.0 with CODE (359) TELE AID emergency call system

Illustrated on model 204.0

Fig 1: Locating Emergency Call System Button

Courtesy of MERCEDES-BENZ USA

Location

The emergency call system button is integrated into the DBE control unit, which is located in the center of the headliner above the inside rearview mirror (A67).

Task

The emergency call system button performs the following tasks:

Triggering of a manual Telematic Alarm Identification on Demand (emergency call system) (TELE AID) emergency call (E-call)
Visual feedback of TELE AID system status in quiescent state, both for automatic and manual TELE AID emergency call

Design

The emergency call system button is designed as follows:

Switch contact
A control resistor in parallel to the switch contact
Cap with inscription "SOS"
2 integrated red light emitting diodes (LED) for displaying TELE AID system status and an integrated LED for the night illumination (circuit 58d)

Function

The manual TELE AID emergency call is made by pressing the emergency call system button labeled "SOS".

The emergency call system button is covered up with a locking flap. Pressing the protective lid unlocks the lid, and it automatically opens with the aid of a spring mechanism. The emergency call system button is designed as a normally closed contact.

In rest position, an electric current flows through the control resistor (in parallel to the switch contact) installed in the emergency call system button. 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 actuating the emergency call system button, the control resistor is bridged by the switch contact. The emergency call system button is read in by the emergency call system control unit via a discrete line. When the emergency call system button is pressed, a manual TELE AID emergency call is recognized by the emergency call system control unit and then transmitted. The emergency call system control unit then intermittently (partially off) actuates one of the two LEDs.

The driver is provided with visual feedback about the actuated function for as long as the manual TELE AID emergency call is active in the form of a flashing LED.

This is also performed for an automatic TELE AID emergency call (triggered by crash signal incl. crash level from supplemental restraint system control unit (N2/10).

In the event of a fault in the TELE AID system, the two red LEDs are permanently actuated by the emergency call system control unit.