Backup Lamp Actuation, Function - GF82.10-P-3011FG

Model 213 up to model year 2021 

Function requirements, general 

• No undervoltage or overvoltage
• Terminal 15 ON

The electronic ignition lock control unit (N73) sends the status of circuit 15 via interior CAN (CAN B) to the front SAM control unit (N10/6).

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 

When reverse gear (transmission 716) or gear range "R" (transmission 725) is engaged, the front SAM control unit activates the backup light actuation.

Vehicles with transmission 716: 

Engaging the reverse gear is recorded by the manual transmission main shifter shaft position sensor (B79/3). The powertrain control unit (N127) reads in the signals of the manual transmission main shifter shaft position sensor directly, generates the "reverse gear engaged" signal and transmits this via the chassis FlexRay (Flex E) to the electronic ignition lock control unit.

Vehicles with transmission 725: 

Gear range "R" is engaged by the fully integrated transmission control unit (Y3/8n4). The fully integrated transmission control unit then sends the "Gear range R engaged" status to the electronic ignition switch control unit over the drive train CAN, powertrain control unit and chassis FlexRay.

The electronic ignition lock control unit uses the incoming information to generate the "Reverse gear engaged" signal, which is independent of the transmission variant, and transmits it to the front SAM control unit via the interior CAN.

The front SAM control unit sends the "Switch on backup lights" request to the rear SAM control unit (N10/8) via interior CAN.

The rear SAM control unit receives this signal and actuates the following components directly:

• Model 213.0/1:
• Left backup lamp (E3e3) in the left rear lamp unit (E3)
• Right backup lamp (E4e3) in the right rear lamp unit (E4)
• Model 213.2:
• Left backup lamp (E3/1 e3) in the inner left rear lamp unit (E3/1)
• Right backup lamp (E4/1e3) in the inner right rear lamp unit (E4/1)

On vehicles with CODE 550 (Trailer hitch), the front SAM control unit sends the "Switch on backup lights" request via interior CAN to the trailer recognition control unit (N28/1), which actuates the backup lights on the trailer via the trailer socket (X58).

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