Backup Lamp Actuation, Function - GF82.10-P-3011RD
Model 172.4 up to model year 2017
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 signals to other road users the intention of backing up and illuminates the road behind the vehicle during reverse travel.
Function sequence for backup light actuation
Vehicles with transmission 711.6 (manual transmission):
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 716.7 (manual transmission):
The engaged reverse gear is recognized via the manual transmission main shifter shaft position sensor (B79/3). The ME/SFI [ME] control unit (N3/10) directly reads in the signals from the manual transmission main shift shaft position sensor and transmits the signal "Reverse gear engaged" via chassis CAN (CAN E) to the front control unit SAM.
Vehicles with transmission 722.9, 725.0 (automatic transmission):
The request to "Engage gear range R" is defined by the corresponding selector lever position.
The electronic selector lever control unit (N15/5) (transmission 722.9) or DIRECT SELECT INTERFACE (N150) (transmission 725.0) transmits the selector lever position via drive CAN (CAN C), CDI control unit (N3/9) (Diesel engine) or ME-SFI control unit (gasoline engine) or chassis CAN to the front SAM control unit.
Two microprocessors are installed in the front SAM control unit, one for control of basic functions, e.g. the exterior lights, and the second for control of 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, which is independent of the transmission version, and sends this via the interior CAN to the rear SAM control unit with fuse and relay module (N10/2).
The rear SAM control unit receives this signal and actuates the left backup lamp (E3e3) in the left rear lamp unit (E3) and the right backup lamp (E4e3) in the right rear lamp unit (E4).
Model 172.4 with transmission 722.9
up to model year 2017
To avoid any brief lighting up of the backup lights when shifting from the "P" gear range to "D" via "R", the request is sent by the front SAM control unit with a delay of t = 500 ms.
| Electrical function schematic for backup light actuation | PE82.10-P-2058-97TAA | ||
| Overview of exterior lights system components | GF82.10-P-9998RD |