Needle chart

dheivic (banned) : very good question indeed!! The illumination level of the dashboard clocks are controlled by 2 x mechanisms; a photo-transistor and a set of adaptation channels that live in the dashboard module.

The photo-transistor is a small round device that's embedded into the tachometer clock between the numerals "7" and "8" like this:-

A photo-transistor is an electronic device whose gain (i.e. amplification level) varies with the amount of light that falls onto its transparent housing.

So, the role of the photo-transistor shown in the picture above is to measure the illumination level INSIDE  the car. The greater the illumination inside the car that results from sunlight entering the cabin, the higher the illumination of the instrumentation clocks. As night-time approaches, the illumination of the dashboard reduces and at some point before dusk, the instrument lighting will switch off entirely. This is deliberately designed as a prompt to the driver to turn-on the headlights.

Whenever the rotary light switch is moved from the "0" position, another mechanism is used to control the dashboard illumination. If the car is fitted with a light-switch that has an "AUTO" position, another light sensor which is designed to measure light levels OUTSIDE the cabin takes over control of the dashboard illumination at low ambient light levels. This light sensor is installed on the windshield just behind the rear view mirror and it looks outwards towards ambient light levels.

You can easily see how the photo-transistor controls dashboard illumination if you shine a torch onto the part of the tachometer clock in my picture above; what should happen is that the clock illumination should increase with the torch light and then decrease when the torch is switched-off.

Don

dheivic (banned). You certainly can - like this:

1. Select the dashboard module @ address hex17
2. Select Adaptation
3. Enter "clock_dial_day" into the search box - select the  6 x "Y" channels like this:
   • dimming_characteristic_curve_adjustment_clock_dial_day-Y1
     
   • dimming_characteristic_curve_adjustment_clock_dial_day-Y2
     
   • dimming_characteristic_curve_adjustment_clock_dial_day-Y3
     
   • dimming_characteristic_curve_adjustment_clock_dial_day-Y4
     
   • dimming_characteristic_curve_adjustment_clock_dial_day-Y5
     
   • dimming_characteristic_curve_adjustment_clock_dial_day-Y6
     These channels define set-points for the illumination level of the clock dials at different daylight levels in the cabin
4. Change the value of these channels to suit your likes using these principles:
   • "Y" number: the lower the "Y" number, the less the cabin daylight level that the channel controls - so Y1 controls clock illumination in the darkest cabin conditions and Y6 controls illumination when the cabin is brightest. 
     
   • Setting: The value for each channel sets the actual illumination level on the clock-dials. The higher the value, the greater the clock-dial illumination level. The permissible values for these channels are 0 to 64 (note: these are hexadecimal numbers - hex64 = decimal 100)
   • Caution 1: I suggest that the factory value of Y1 and Y2 is NOT changed because these values result in the clock illumination switching off during dusk conditions - this provides a visual prompt to the driver to turn-on the headlights. This is a safety feature that is worthwhile keeping.
     
   • Caution 2: Take note-of (meaning "write-down") the default factory values for the 6 x adaptation channels BEFORE making changes; you may need to revert to the original values if necessary
     
5. At some point in the process, OBD11 will ask for a security code. If your car was built before mid 2016, use 20103. If the car is a later model, use 47115
   

Examples:

• Brightest clock illumination:
  • Y1-00
    
  • Y2-03
    
  • Y3-64
    
  • Y4-64
    
  • Y5-64
    
  • Y6-64
  
  
• Moderate clock illumination:
  
  • Y1-01
    
  • Y2-03
    
  • Y3-10
    
  • Y4-20
    
  • Y5-46
    
  • Y6-64

Don