MB-Info and breakdown assistance button group, component description - GF82.95-P-3211CWU
MODEL 204.0 with CODE (359) TELE AID emergency call system
Illustrated on model 204.0
Location
The MB-Info button and the breakdown assistance button are integrated into the DBE control unit, which is located in the center on the headliner above the inside rearview mirror (A67).
Task
Pressing the MB-Info button (letter "i" as symbol) actuates the MB-Info call and pressing the breakdown assistance button (wrench as symbol) actuates the breakdown assistance (Roadside Assistance) function. Moreover, the current operating state is indicated to the driver by the respective integrated LEDs.
Design
The MB-Info button and the breakdown assistance button are designed as follows:
- One integrated LED each for the night illumination (circuit 58d)
- One integrated LED each for displaying operating states (MB-Info call or breakdown assistance)
- The MB-Info button and the breakdown assistance button each have a control resistor connected in parallel to the switch contact
Function
In rest position, an electric current flows via the installed control resistors of the MB-Info and breakdown assistance buttons (in parallel to the switch contact). The emergency call system control unit (N123/4) thus knows that the voltage supply lines and the ground line are OK. When the MB-Info button or the breakdown assistance button is actuated, the respective control resistor is bridged by the respective switch contact.
The MB-Info button and the breakdown assistance button are read in via 4 discrete lines by the emergency call system control unit. If the MB-Info button or the breakdown assistance button is pressed, the emergency call system control unit transmits the corresponding request. The emergency call system control unit then intermittently (partially off) actuates the particular LED.
The driver is provided with visual feedback about the actuated function for as long as the relative function is active in the form of a flashing LED.