Low volume

Wakeboarding

Last year I had a new polk audio amp and speakers installed in my boat on the wakeboard tower. I used it for a total 2 hours last year after they were installed. Put the boat in the garage over the winter and took it to the lake this year and all i get is a very low volume out of the speakers. The other amp and speakers are fine. Light is on on the amp. All the connections seem to be good. Hope someone can help????