Roof function centre

In the Basic version, the roof function centre is not an autonomous control unit.

The roof function centre contains the following components, depending on the equipment fitted and the national-market version:

  • Interior light
  • Reading lights (for driver's side and front passenger side)
  • Light-emitting diodes for ambient lighting
  • Indicator lamp for front passenger airbag deactivation
  • SOS button with emergency call LED
  • Interior light button
  • Button for reading lamp on the driver's side
  • Button for reading lamp on the front passenger side

Functional description

The following functions are described for the roof function centre:

  • Interior light

    The interior light is automatically activated by the footwell module (FRM) or the front electronic module (FEM). The interior light can be switched on or off manually using the interior light button in the roof function centre.

  • Reading light

    The reading lights are supplied with voltage by the footwell module (FRM) or the front electronic module (FEM). In the roof function centre the provided voltage supply provided is only looped through. Pressing the corresponding button activates the selected reading lamp.

  • Ambient lighting

    The 2 LEDs for the ambient lighting are activated directly via the footwell module (FRM) or the front electronic module (FEM).

  • Indicator lamp for front passenger airbag deactivation

    The Crash Safety Module (ACSM) activates the indicator light for the passenger airbag deactivation directly. In the roof function centre, the indicator light for the front passenger airbag switch-off is connected to terminal 30B. When the indicator light lights up, the front passenger airbag is deactivated.

  • SOS button with emergency call LED

    The emergency call button with emergency call LED is directly connected to the telephone control unit. In the roof function centre, the emergency call button with emergency call LED is connected to terminal 31E.

    Triggering an emergency call:

    • Touch the covering flap of the emergency call button and open it.
    • Press the emergency call button until the emergency call LED lights up. The connection is established.
    • When the emergency call LED flashes, the connection has been established.

    The manual emergency call can be cancelled within 5 seconds.

In the roof function centre, the voltage supply provided by the front power distribution box for the vanity mirror lights is only looped through.

F12 shown

Index Explanation Index Explanation
A Roof function centre, front view B Roof function centre, rear view
1 Emergency call button 2 Emergency call LED
3 Interior light 4 Left-side reading light
5 Left-side ambient light 6 Button for left-hand reading light with locator lighting
7 Interior light button with locator lighting 8 Right-side ambient light
9 Button for right-hand reading light with locator lighting 10 Reading light, right
11 Indicator lamp for front passenger airbag deactivation 12 Bulb holder (reading light, left)
13 Bulb holder (interior light) 14 Bulb holder (reading light, right)
15 10-pin plug connection 16 eight‐pin plug connection

Structure and inner electrical connection

The roof function centre is connected to the vehicle electrical system by 2 plug connections.

Index Explanation Index Explanation
1 Left-side reading light 2 Left-side ambient light
3 Interior light 4 Interior light button with locator lighting
5 Right-side ambient light 6 Reading light, right
7 Button for right-hand reading light with locator lighting 8 Indicator lamp for front passenger airbag deactivation
9 Emergency call button with emergency call LED and locator lighting 10 Button for left-hand reading light with locator lighting

Pin assignments

Pin Explanation
Terminal 30B Terminal 30B, base operation
Terminal 31E Terminal 31, electronics earth (ground)
Terminal 58g Terminal 58g, locator lighting
SIG1 Signal line for status display emergency call LED of the telephone control unit
SIG2 Signal line for button signal of the emergency call button at the telephone control unit
SIG3 Signal line to indicator light for passenger airbag deactivation from Crash Safety Module (ACSM)
U Supply voltage for the interior light of the footwell module (FRM) or front electronic module (FEM)
U2 Supply voltage for the reading lights of the footwell module (FRM) or Front Electronic Module (FEM)

Nominal values

Please observe the following setpoint values for the roof function centre:
Size Value
Supply voltage 9 to 16 V
Temperature range -40 to 85 deg C

Diagnosis instructions

Failure of the component

If roof function centre components fail, the following behaviour is to be expected:

  • Failure of indicator light for passenger airbag deactivation Fault entry in the Crash Safety Module (ACSM) and Check Control message in the instrument panel.
  • Failure of emergency call button or emergency call LED: Fault code entry in the telephone control unit and Check Control message in the instrument cluster.

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