Audio Systems: VW Passat sound distortion when lights are on, light dimmer circuit, vw passat

Question
I have a 1999 Passat that has a lot of noise on the AM radio frequency.  It is a very high pitched, shrill sound.  The problem gets even worse when I turn on the headlights.  I've never run into headlights playing a role in interference.  By the way, the VW running lights are always on when the engine is running (you probably already know that) and the shrill sound increases when I turn the light switch to the full on position to light the instrument panel.  Is there something simple I can do or do you think I need to take it somewhere to be fixed?  I'm not a "gifted" repair person and definitely don't know a thing about auto wiring.  Thanks for any help you can give me.

Answer
Rick,
With most vehicles today unless you are tuned to a very strong AM station the electrical noise from the engine computer/s and wiper/heater motors will over ride the AM stations. The noise that you are hearing when you turn on the head lights may be from the dimmer control circuit for the panel lights. A noise filter on the input and outputs of the light dimmer circuit may help to reduce the noise.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net