Originally Posted by turbo510
My '05 3.0 sometimes keeps the tail lights lit, no matter what the light switch position, and even after unlocking and relocking the car. I'd appreciate any advice from someone who has solved this.
If it's your brake lights and not tail lights that are staying on (which I believe is the case, since you mentioned they stay on even when you lock the car), I can say with reasonable certainty it's the brake light switch, which is actually a common issue with our model A4 and some VWs as well. Audi/VW use the same part, which becomes defective after a while (this happened to my car, the brake lights would turn on by themselves after the car was parked for a couple hours). You can test this out by having someone stand behind the car while you pull up slightly on the brake pedal, if the lights turn off, it's definitely the switch.
There's a good write up on this VW forum on how to change the switch, you can easily do it yourself:
If it's not the brake light switch, it may be a short somewhere, or possibly the light switch is defective, I don't really have any other good suggestions.