Other functions

The footwell module (FRM) influences various functions in the vehicle. The following components are controlled by the footwell module:

• Exterior mirrors
• Exterior lighting
• Interior lighting
• Central locking system
• Power windows

  Exterior mirrors 

  The requests to adjust the mirror are sent via the LIN bus. The footwell module (FRM) receives and processes the signals via the LIN bus. Every 20 milliseconds, the footwell module queries whether there are requests from the switch block.

  In the Sleep mode, the power supply is switched off. The outside mirrors cannot be actuated.

  The mirror heating on the outside mirrors (optional extra) is activated by the footwell module. The corresponding information is forwarded to the evaluation electronics in the mirror via the LIN bus.

  If a mirror memory is installed, the footwell module saves the memory position of the mirrors.

  Exterior lighting 

  The lighting function are integrated in the footwell module (FRM).

  These lighting function are:

  • Side lights
  • High-beam headlight
  • Headlight flasher
  • Turn indicator
  • Hazard warning flashers
  • Brake light
  • Low-beam headlights
  • Reversing light (signal for reversing light comes from electronic transmission control via bus or from reverse gear switch)
  • Fog lights
  • Rear fog light
  • Parking light

  Besides the lighting functions, other exterior lighting functions are also integrated in the footwell module:

  • Light monitoring
  • Headlight beam throw adjustment
  • Emergency operating mode if the footwell module fails
  • (important lighting functions are substituted by other lights being actuated in the event of individual lights failing.)
  • Headlight courtesy delay feature
  • Visual alarm after triggering of the anti-theft alarm system (the visual alarm is issued according to the coding by hazard warning lights, flashing with low-beam headlights or flashing with high-beam headlights.)
  • Activation of bi-xenon headlights
  • Activation of the step motor controller for the adaptive headlights
  • Turning lights The cornering light is coupled to the Adaptive Headlight.

  All lighting functions except the additional brake light are supplied with a pulse-modulated signal by the footwell module (FRM). This PWM signal enables a uniform brightness of the exterior lights.

  Interior lighting 

  On vehicles without roof function center (FZD), the footwell module actuates the interior lighting in the roof area directly. All footwell module outputs for interior lighting are pulse-width modulated. This ensures that the interior lighting maintains constant brightness despite voltage fluctuations.

  With standard equipment, the interior lighting comprises the following components:

  • Front interior light
  • Luggage compartment lights
  • Glove box light
  • Footwell lighting

  The following components can also be installed as special equipment for the interior lights:

  • Rear interior light
  • Ground lights

  Central locking system 

  The footwell module evaluates the status of the Hall effect sensors in the door contacts. When the vehicle is locked or unlocked with the mechanical key element, the footwell module will recognise this request. The footwell module transmits a message on the K-CAN to the CAS (Comfort Access System):

  Power windows 

  The footwell module (FRM) and the junction box electronics (JBE) control the power window drives. The relays for the front power windows motors are located in the footwell module. The relays for the rear power window drives are fitted in the junction box electronics.

  Electric steering column adjustment 

  The electrical steering column adjustment enables the driver to set the optimized position of the steering wheel. There is a switch on the left of the steering column for operation. The inclination and length of the steering column are adjusted electrically.

  Power for the electrical steering column adjustment is provided via terminal 30 switched. The footwell module (FRM) activates the electrical steering column adjustment (FRM).

  When the steering column is adjusted, a Hall sensor on the steering column adjustment motor sends a signal to the FRM control unit. The position of the steering column is registered by and stored in the FRM control unit.

  For the key memory, this means that the position of the steering column can be called up.

  To support entry and exit, the tilt adjustment moves to the highest position. For Easy Exit, the steering column adjustment is automatically activated under the following conditions:

  • Terminal R OFF
  • Terminal R ON and driver's door opened (signal via door contact)
  • Terminal 15 OFF with driver's door open (signal via door contact)

  The steering column memory is activated under the following conditions:

  • One of the two memory buttons is pressed (from terminal R ON).
  • Another identification sensor is used (personalization).

  Precondition: The selection "Last seat position after unlocking" is activated in the "Settings" menu in the Central Information Display (CID).

  In both cases, the steering column memory only moves to the corresponding memory position after terminal 15 On.

Notes for Service department 

Nearly all Car and Key Memory functions are programmed inside the vehicle itself. (Please refer to the "Personal profile" section of the Owner's Handbook: Individual settings for up to 3 remote controls via the display in the instrument panel or via the Central Information Display)