Well, it certainly seems odd to me. New VW Beetle (Turbo S if you care) and there is a problem with the left rear brake/tailight. With just the headlights on, the tailight is just fine (normal illumination, same as the other taillight). With the headlights off, the brake light works just fine (bright, same as the otehr brake light). But when the headlights are on, and the brakes are applied the left rear light goes completely off. Remove the brake and it goes back to normal taillight brightness.
So to recap: taillight alone is good, brake alone is good, brake and taillight together is no light.
When it was in this mode, I removed the taillight assembly and by the time I had it out and ready to be looked at, damn if it wasn't working correctly. Put it back in and it was good for a day or so, then back to bad.
Any ideas of where to look would be greatly appreciated.
-Jim