I have a 2005 Mercedes Benz Viano. It has an instrument panel (speedo, rev counter, etc) with a small orange LCD display. It looks a bit like this:

Mercedes Dash spare part

Sometimes, after about an hour's driving, the backlight on the LCD panel goes off (so the orange light in the image above fades to nothing). The vehicle has not yet been driven in the dark, it has only been driven in fine conditions during the day, so I do not know if this is just the LCD or all backlighting.

My questions are:

  1. Has anybody seen this before and if so can you suggest a fix?
  2. If the LCD panel fades out, does this also mean that the illumination on the speedometer and other dials would also fade out (but I have not noticed it, because this was during the day) --- or is the backlight of the LCD on a separate circuit from the backlight of the dials, so that if one goes off the other may still be operational?

I hope this is clear. Comments welcome. Thank you.

  • Welcome to Motor Vehicle Maintenance & Repair! Commented Jul 14, 2020 at 14:14

1 Answer 1


LCD failures are common, and it could be the backlight or the entire LCD. From a repair point of view it doesn't matter which it is as the LCD/backlight is a unit which has to be replaced as one, it's not repairable. This shouldn't impact the other lights, if it does then the LCD unit isn't the problem.

As for what to do unless you are really good with electronics and have a lot of test equipment the best option is to send the instrument panel off to a specialist for repair. You can replace it, generally a new one will have to be reprogrammed for your car, which makes it a more expensive option.

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