3rd Brake Light

I am having problems with my 05 A4 1.8T Quattro. The signal telling me the 3rd brake light is out turns on and off. Sometimes it will go 2 months and never signal a problem then for a few days stright it will flash that the brake light is out. When driving at night and the signal flashes I can see the brake light does not turn on and when all is okay I can see the red glare of the light turning on. Audi told me it was the connection to the 3rd brake light and fixed it but that solution has not lasted longer then 3 days before it occured again. ANY IDEAS????

Check the connector at the light make sure its not loose at all.