# Dash lights dimming in and out, any ideas?



## vee-tread (May 15, 2011)

If I keep an eye on my dash while driving or when I'm idling, I can randomly see the entire dash (speedometer, tach area) dims very quickly.
I tried raising the radio volume and base to see if it was a general power issue, but that didn't make difference.
Headlights don't dim either.

This also occurs when its 100% bright outside, or dark, so I know its not a dash light sensor getting confused because of the time of day.

Does this sound like a switch gone faulty?
I would think if it was the alternator the headlights and other interior lights would dim.

What do you guys think?


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## tekmo (Nov 30, 2013)

hmm i have not noticed this. I will keep an eye out tomorrow.


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## qtroCUB (Mar 22, 2005)

Instrument lights will dim and brighten due to the direction of where light is coming from. I'd you are heading into the sun the car assumes that you cannot see the dark gauges and will brighten them. 

To test it out. Shine a flashlight into the light sensor on the non-mirrored side of the rear view mirror. 

Same thing happens in the TTS.


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## vee-tread (May 15, 2011)

I understand where you are coming from. Also I didn't know that the light sensor was located there.
But what I experienced happens when the car would idle too (after a drive), in the evening. So I would assume the light would be content.

Also to clarify this dimming, I mean the light intensity fluctuates. I see it happening super quick as well as a typical ascending/descending light intensity.
By quick I mean like a flicker of a moment the light dims down and back up.

Thanks for your input


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## A3_yuppie (Jun 5, 2006)

qtroCUB said:


> Instrument lights will dim and brighten due to the direction of where light is coming from. I'd you are heading into the sun the car assumes that you cannot see the dark gauges and will brighten them.
> 
> To test it out. Shine a flashlight into the light sensor on the non-mirrored side of the rear view mirror.
> 
> Same thing happens in the TTS.


The speedometer and the tachometer dim to almost off when you enter a dimly-lit area (e.g., underground parking) to remind you to switch on your headlights.


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## rabbitgtibbar (Apr 29, 2002)

There is, IIRC, the classic dash brightness adjustment rheostat on the A3. It's certainly possible you have a faulty one of those.


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