How do I connect the lights on my boat trailer to an Audi Q7?

I have a 2007 Audi Q7 with a factory installed towing package. I attached a converter to change the 7-pin electrical to a 4-pin flat connector for my boat trailer. When first connected yesterday, a light flashed on the dashboard, indicating a trailer was connected. The lighting worked fine. Today, the lights do not work, and there is no indicator on the dashboard. What could be wrong?|||Check for an in line fuse on your trailer harness, it could be blown.