Brief component description
The following components deliver signals for the footwell module:
- Ride height sensors
- Brake light switch
- Reversing light switch
- Hazard warning switch
- Light switch
- Assist systems operating facility
- Driver's door switch block
- Door contacts of the front and rear doors
- Driver's door lock
A number of control units are involved in the lighting system. In a stricter sense, the following control units are involved in the lighting (in alphabetical order):
- ACSM: Crash safety module
ACSM stands for "Advanced Crash Safety Module", referred to as the crash safety module.
The footwell module is connected to the Crash Safety Module via the K-CAN. In the event of an accident with corresponding severity, the footwell module switches on the interior light and the hazard warning lights automatically. The crash safety module sends a message regarding the front passenger seat occupation detection on the K CAN. The belt handover on the passengers side is only activated when the front passenger seat is occupied.
- AHM: Trailer module
The trailer module delivers the signal indicating whether a trailer is attached to the vehicle. The trailer module also controls the trailer lighting.
During trailer towing, the trailer module automatically disables e.g. the rear Park Distance Control (PDC) and the rear fog lamp on the vehicle.
If a trailer is detected, the automatic parking function is disabled. (Automatic parking function: To improve the view of the kerb, the outside mirror glass is folded downwards when reverse gear is engaged. This brings the lower area immediately around the vehicle, i.e. the kerb, into the field of vision.)
The trailer module (AHM) is connected to the footwell module via the K-CAN.
- DSC: Dynamic stability control
When cruise control is in operation, the brake lights are actuated during automatic braking (legal requirement). To do this, a signal must be sent from the DSC to the accelerator pedal module via the PT-CAN.
- EGS: Electronic transmission control
If reverse gear is selected with an automatic gearbox, this information is sent to the footwell module via the vehicle busses. The footwell module then switches on the reversing lights.
In vehicles with a manual gearbox, the reverse gear switch is directly connected to the footwell module.
- FLA: high-beam assistant
In accordance with the traffic situation, the high-beam assistant sends a switch-on recommendation or a switch-off recommendation for the high-beam headlights to the footwell module (FRM). On the basis of this recommendation and various other the input variables, the footwell module decides whether the main-beam headlights should be switched on or off.
- FRM: Footwell module
The footwell module is connected to the vehicle with 3 plug connections. Two 51-pin connector connect the main wiring harness. Another 26-pin connector is for the connection to the dashboard.
- FZD: roof function center
The roof function center is responsible for the components of the interior lighting in the roof area.
The Basic variant of the roof function center has its own control unit. The front interior light and the rear-compartment interior light are activated via the footwell module (FRM).
The High variant of the roof function center has its own control unit, the FZD control unit.
The footwell module is connected to the FZD control unit via the K-CAN.
- JBE: Junction Box Electronics
The lighting for the luggage compartment and the glove box lighting are connected to the junction box electronics.
- LDM: Longitudinal dynamics management
In conjunction with the LDM, the option "Active Cruise Control" uses the "turn signal" from the footwell module to help when changing lanes. In other words, if a left turn indicator is given before overtaking, the distance to the vehicle in front is reduced. The vehicle to be overtaken is then "lost" more quickly. On the other hand, when changing to the right-hand driving lane, a vehicle moving there is picked up more quickly.
- RLSS: Rain/light solar sensor
The rain/light sensor measures the ambient brightness outside the vehicle. Depending on the ambient lighting conditions, the footwell module will switch the driving lights on or off. To do this, the automatic driving lights control must be activated (light switch in switch position "A"). At dusk, the rain-light sensor sends the message "dusk". The footwell module switches the low-beam headlight on. The automatic headlight-range adjustment for the dipped-beam headlights is actuated. In darkness, the rain/light sensor transmits the message "Darkness". The adaptive headlights are then activated when the vehicle is cornering.
After driving through a tunnel or when driving out of the garage, the driving light can remain switched on for up to 2 minutes. This is not a fault, but an intentional function to prevent the light being switched on and off continually.
- SZL: Steering column switch cluster
The switch signals from the turn-signal/high-beam switch are picked up and evaluated by the SZL. The evaluated switch signals are forwarded as resistance-coded by the SZL via direct lines to the footwell module
- Switch block, driver's door
The driver's door switch block is connected to the footwell module via a LIN bus.
The driver's door switch block contains the buttons for the power windows, the outside mirror adjusters and the folding function for the outside mirrors (only with outside mirrors that are equipped with this feature as an optional extra) as well as the buttons for the child locks and the rear window roller sunblind.
- Assist systems operating facility
The driver assistance systems operating unit is connected to the footwell module by a LIN bus.
The operating unit contains button for the following driver assistance systems:
- Lane departure warning
- Head-up display
- Night vision
- Dynamic Braking Control
- Lane departure warning
The following components are activated by the footwell module:
- Exterior mirrors
- Front power window drives
- Headlight
- Tail lights
- Fog lights
- Additional brake light
- Side repeater
- Ground lights
- Ground lights
- Number-plate light
- 2 headlight driver modules for the step motors of the adaptive headlights
- Electric steering column adjustment