Backup lamp actuation, function - GF82.10-P-3011FLM

MODEL 212 as of model year 2014 

Function requirements, general 

• No overvoltage or undervoltage
• Terminal 15 ON

The electronic ignition lock control unit (N73) transmits the circuit 15 status to the front SAM control unit with fuse and relay module (N10/1) over the interior CAN (CAN B).

Backup light actuation, general 

The backup light actuation enables the traffic lane to the rear of the vehicle to be illuminated when backing up.

Function sequence for backup light actuation 

Backup light actuation is activated when reverse gear (with transmission 711 or 716) or gear range "R" (with transmission 722.9, 724.2 or 725) is engaged.

Vehicles with transmission 711 or 716:

Engagement of the reverse gear is defined through the status of the backup lamp switch (S16/2), which is read in directly by the front SAM control unit.

Vehicles with transmission 722.9, 724.2 or 725:

Gear range "R" is engaged by the fully integrated transmission control unit (Y3/8n4). The fully integrated transmission control unit then transmits "gear range R engaged" status to the front SAM control unit via the drive train CAN (CAN C), the CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) and chassis CAN 1 (CAN E1).

Two microprocessors are installed in the front SAM control unit, one for controlling basic functions such as the exterior lights, and the second for controlling the central gateway functions. Both processors communicate with each other internally via interior CAN.

The microprocessor for controlling the central gateway functions uses all incoming information to generate the "Reverse gear engaged" signal that is independent of the type of transmission, and transmits this via the interior CAN to the rear SAM control unit with fuse and relay module (N10/2) and also to the trailer recognition control unit (N28/1) in vehicles with code 550 (Trailer hitch).

The rear SAM control unit receives this signal and actuates the left backup lamp (E3/1e3) in the left rear inner lamp unit (E3/1) and the right backup lamp (E4/1e3) in the right rear inner lamp unit (E4/1).

The trailer recognition control unit receives this signal and actuates the backup lamp on the trailer via the trailer socket (X58).

	Electrical function schematic for backup light actuation		PE82.10-P-2058-97DAB
	Overview of exterior lights system components		GF82.10-P-9998FLM