When i am driving at night with my headlights on, I can hear a loud buzzing noise coming through the speakers, and the screen doesn't dim. Once i open a door the screen dims and the buzzing noise goes away. When i shut the door the screen gets bright again and the buzzing comes back. The unit is functioning correctly during day driving. Does this sound like tyhe illumination wire is loose, or do i have a short somewhere? any ideas?

thanks in advance!

What unit do you have? What vehicle do you have it in?

Always check the ground first.

Its a 2004 Audi S4 with a D3.

Update:

The loud buzzing noise is not coming from my speakers but rather from behind the dash. Really need some help on this one.

I got the same problem in my Audi a4 (2007).

As far as the unit dimming, it sounds like whoever hooked it up connected the illumination wire from the D3 to the overhead lamp in your car. You need to connect it to a source the puts out 12v when the headlights go on.

Thanks, i had the shop remove the illumination wire from wherever they had it, ill ask if they used the overhead lamp.

really curious to get an answer on this as well. i get the same buzz (almost rotary-like or oscilating type sound)) from within the dash. i get this sound at 50 mph or higher. the sound tends to lessen when i remove my foot from the throttle.

FYI: I'm in a 2007 Toyota Tundra

really curious to get an answer on this as well. i get the same buzz (almost rotary-like or oscilating type sound)) from within the dash. i get this sound at 50 mph or higher. the sound tends to lessen when i remove my foot from the throttle.

 

FYI: I'm in a 2007 Toyota Tundra

cancel that. the buzz was caused by my bug deflector!

after talking more with the installer, i learned that he used a relay between the illumination wire and the headlight connection. Apparently, my audi had the signal backwards, putting out 12V when the lights were off and 0V when they were on. My installer has removed the relay as i suspected it was causing the problem. Any ideas on how to wire this up if in fact the connection sends "opposite" voltages from the expected. or does it sound like my illumination is tapped into the wrong place?

TIA

sounds to me like your installer will have to wire the illumination wire from the avic unit to a parking light bulb (can be found front or rear, rear probably easier) to get a good signal. most of the vw/audi group cars use a resistance to 12v signal for the lights, so he was probably going to the switch for lighting. there is no lighting signal for the factory radio ( i think) because it gets its info from the canbus databus. that would be confirmed if he had to run a swithed power lead for the avic. it is sad to say, but this type of computer controled lighting is becoming more prevalent these days.

sounds like a good idea, ill have the installer try a parking light.