Hello, i currently have a 2007 x350 3.0 i have noticed that non of the buttons on the dash steering wheel doors are lighting up aswell as the clock it seems that none of them are working has anyone experienced this before and knows where to start with this
cheers in advance

 

Check the 10 amp fuse F14 in the passengers junction fuse box.
That supplies all those instrumentation lights you have mentioned via the front electronics module.

 

I have checked that fuse it seems to be okay is there any other fuses that are linked to that system

 

Supply voltage comes from F10 into the front electronics module (FEM) 20 way black plug (CR85) on pin 1 (Brown/White stripe).
The clock illumination is separately driven out of FEM via the same 20 plug but on pin 11 (Red/White stripe).
The rest of your front instrumentation illumination mostly is fed out of a common output on Pin 12 of the same 20 way connector (also a Red/White stripe wire).

If you download a electrical schematic for the car (refer to the stickies at the top of the X350 forum) you will find the relevant section of the Dimmer controlled lighting part 1 schematic on Fig. 9.2

If the dimmer control is not working, then check fuse F47 (5 Amp) in the passengers junction fuse box. That supplies some of the logic of the instrument panel that also processes the dimmer control input. Fig. 9.2.
Check that you have a variable voltage at the Auxiliary lighting switch 10 way connector IP33 Pin 8 (Red/White stripe). That voltage should sweep up and down as you turn the rotary dimmer control.
Note: the schematic may have a printing error as the auxiliary lighting switch connector is stated as IP33 in the drawings but referred to as IP50 in the connector description key on the preceding page.

My gut feeling is you may have lost the dimmer control line to the instrument panel either through a wiring fault or the auxiliary control switch assembly, as if as you say you have no clock illumination either (barring failed lamps in the clock) then it is unlikely you have two independent separate FEM outputs that have failed simultaneously. The reason for two separate outputs is the clock has small bulbs and the general instrument illumination are LEDs.

 

Supply voltage comes from F10 into the front electronics module (FEM) 20 way black plug (CR85) on pin 1 (Brown/White stripe). Is this pin the power supply to the lighting of the buttons or does that come from the dimmer switch also for the dimmer switch does it have one wire to control the dash and buttons or do they split off it to 2 as the instrument clutster dimes as it should thank you for the help btw much appreciated

 

CR85 Pin 1 is the common 12 volt supply feed for the majority of the switch pack instrumentation lighting.
The dimmer control supplies an analogue voltage input reference to the instrument cluster that then digitizes it for sending to the FEM so it can drive the two separate outputs on CR85 pins 11 and 12.

Oddly there is no direct reference to what supplies the instrument cluster lighting, so I suspect that the instrument cluster may create its own local PWM illumination voltage internally to drive its internal LEDs seeing the dimmer assembly directly terminates into the instrument cluster that then on-sends dimming information via data to the FEM.

Note: the FEM outputs to the LEDs and clock will be pulse width modulated (PWM), not an analogue DC output.
The clock lighting not working might also be a red herring if you happen to have blown bulbs in it, so you might want to check the PWM drive voltage on CR85 pin 11 to see if you have drive there. That channel output of the FEM might be perfectly fine and just the clock faulty.