Try to replace a low beam bulb first it will be the cheapest diagnostic test you can do. If the bulb fixes the problem replace the other one if not you will have to start tracing wires and power supply to the switch and looking for wiring damage and blown fuses. There is a company that independent auto repair shops "buy" their information from that offer a very reasonable service to do it yourselvers. You can get a one week subrcription or year subscription very cheap. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... great quality information same as the professionals have ,much better than generic workshop manuals from parts stores, much cheaper than the factory manual try http://www.eautorepair.net/Marketing/Default.asp?VID=125669 and get an online repair manual subscription.
Vw wiring diagrams are not easy to read for someone not experienced in electrical circuits. You need to print up several diagrams and tape them together then go out to your car and se if you can figure out the problem.
