Hazard Warning Lamps: Description and Operation

GF82.10-P-3080CW Substitute Lights And Emergency Lights Actuation, Function

Function sequence for substitute lamp actuation
If specific lights malfunction, then others are actuated as substitutes, if necessary by pulse width modulation (to adapt the light output). In such an instance, flashing functions have priority over steady light.

The extent of the substitute lamp actuation depends on the country and is integrated in the front SAM control unit with fuse and relay module (N10/1) (see table below).

Lamp failure check:
A lamp defect is displayed as text in the multifunction display (A1p13) of the instrument cluster (A1).







Emergency light function
Function requirements:
^ Circuit 15 On

Function sequence for emergency light function
The aim of the emergency light function is to prevent that due to a single error (e.g. failure of the front SAM control unit or failure of the interior CAN) the complete front or rear vehicle illumination fails.
For this reason, the front SAM control unit and the rear SAM control unit with fuse and relay module (N10/2) each have separate hardware which guarantees the emergency light function. In the event of failure of the interior CAN or a SAM control unit, the exterior lights are activated as follows within t < 3 s when the ignition is switched on.

By the front SAM control unit:
^ Left low beams (E1e2) and right low beams (E2e2) (without code (614) Bi-xenon headlamp unit and without code (622) Intelligent Light System (right-hand traffic))
^ "Low beams" request to the left xenon light control unit (E1n1) and to the right xenon light control unit (E2n1) (with code (614) Bi-xenon headlamp unit or with code (622) Intelligent Light System (right-hand traffic))
^ Left front standing light and parking light (E1e3) and right front standing light and parking light (E2e3)
^ Left front standing light 2 (E1e12) and right front standing light (E2e12) Front left side-marker lamp (E6/1) and front right side-marker lamp (E6/2) (United States Of America and Canada only)

By the rear SAM control unit:
^ Left brake light and taillight and parking light right brake light and taillight and parking light
^ Inner left brake light and taillight inner right brake light and taillight
^ Left rear fog lamp
^ Left rear side-marker lamp and right rear side-marker lamp
^ Left license plate lamp (E19/1) and right license plate lamp (E19/2)
^ Center brake lamp (E21)