Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Switch-On Conditions
The footwell module (FRM) receives a large number of input signals that switch on the interior lighting. The input signals are directly read into the FRM or are received via the K-CAN.
The following signals switch the interior lighting ON:
- Interior lighting button pressed
- Door opened
- Vehicle unlocked at driver's door lock cylinder
- Vehicle unlocked with remote control
- Terminal R OFF, if terminal 58g was ON no more than 2 minutes earlier
- Crash signal
- Lock button on remote control pressed when central locking system has been in central double-locking for at least 10 seconds
The interior lighting is switched off under the following conditions:
- Central locking system set to thief-proof mode, all doors and the tailgate closed
- Interior lighting button pressed for longer than 3 seconds
- Terminal 58 ON and terminal R OFF
- Terminal R ON with doors closed
- The vehicle is unlocked with the remote control and no door is opened with the space of 20 seconds
- Terminal R OFF and a car door left open for longer than 1 minute
- "Power Down" via diagnosis
- 16 minutes after terminal R OFF
When terminal R is switched OFF, the footwell module (FRM) will switch the interior lighting off after 16 minutes. To do this, the FRM sends the message for consumer shutdown via the K-CAN. The roof control panel (FZD) receives this message and switches off the interior lighting in the roof area. Interior lights that are switched on directly by the FRM are also switched off.
The FRM makes terminal 58 g available via K-CAN or via conventional wiring. Terminal 58 g is pulse-width modulated and has two brightness levels.
- Brightness level for locating lights
The brightness for the locating lights can be set individually with the rocker switch on the steering column stalk.
- Brightness level for function lighting
The brightness level for function lighting is not dimmed and is switched on at full intensity.
As soon as the hazard warning lights switch is pressed, the hazard warning lights switch illumination is switched on at full intensity by the FRM. If terminal 58 g is activated, the hazard warning lights switch will no longer be illuminated with full intensity. Brightness depends on the setting for the locating lights.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.