Backup Lamp: Description and Operation

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

Function requirements for backup light actuation in general
^ Circuit 15 On

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

Backup lamp actuation function sequence
The terminal status of circuit 15 is sent to the rear SAM control unit with fuse and relay module (N10/2) from the EIS [EZS] control unit (N73) on the interior CAN.

Vehicles with transmission 716:
Engaging reverse gear is recognized by the backup light switch (S16/2). The "reverse gear engaged" status is directly read in by the driver SAM control unit with fuse and relay module (N10/1) and sent to the interior CAN.

Vehicles with transmission 722:
The request to engage the R gear range is defined by the corresponding selector lever position and output by the electronic selector lever module control unit (N15/5) on the engine compartment CAN.

The electronic transmission control control unit (N15/3) (with transmission 722.6) or the fully integrated transmission control unit (VGS) (Y3/8n4) (with transmission 722.9) receives the request to engage the R gear range, implements it and provides the "gear range R engaged" status to the engine compartment CAN.
The central gateway control unit (N93) receives the corresponding status and routes it on the interior CAN to the rear SAM control unit, which then actuates the left backup lamp (E3e3) and the right backup lamp (E4e3).

To avoid any brief lighting of the backup lamps when changing from gear range P to D by way of R, the "gear range R engaged" status is sent with a delay (t = 500 ms).