I have had an Eclipse AVN826 radio/GPS, etc fitted into the Touareg. Unfortunately the connection to the headlights (used for turning down the screen brightness) has become disconnected and my auto electrician has not been able to find where it was connected to. I would assume the OEM radio would have had a connection to the instrument lights. Has anyone any idea what wire would carry out this task. I was going to download the service manual however I use a mac computer and it seems it is not compatible. Any help would be appreciated.