Can anyone please help me.

I recently switched cars to a 2006 Octavia II Combi.

As the car had no headunit I bought a radio/DVD/tft 1-din hu that I installed into the car.

After installing, I noticed a very annoying buzz from the front speakers, but only if the lights are on.

Pressing the brake reduces the buzz and switching the fogglights on while breaking resolves it completely.

I have tried without connecting the ground cables and using continuous power instead of ignition switched. This helps but doesn't completely remove the problem.

On the Dutch skodaforum.nl I saw that this problem has been noticed by several people but no sollution is added.

Does anyone have an idea? My dealer offered to look at the problem, but charges EUR 66,70 excl. taxes per hour!

Have you tried checking the ground at the headlights. It would seem to me that it is probably insufficent and is adding 'noise' to the car electrical system.

You need to ensure the power supply to the headunit is properly filtered. The noise from the xenons is the electronics used to alter the power to the headlamps. This will feed back to the 12v system but good filtering should eliminate most of it.

I had a DVD player that was earthed in a different place to the head unit and the noise was unberable due to the ground loop interference. Once the DVD was earthed to the same wire as the headunit the noise was almost eliminated.

OK. I narrowed it down to the antenna.

Seems that the carkit preperation from the factory interferes with my stereo.

For now I simply unplugged the FAKRA connector but am now lacking FM reception.

Anyone knows what to do next?

My next step would be to remove the dashboard on the passengers side to cut off on of the antenna cables.

Take it back to the dealers and ask them to provide a solution.