Re: 2006 crestliner sportfish 1850
Go to an auto parts store and get a 12v test light. Pull fuses one at a time and go from one side of the fuse holder to the other with the test light. When you find one that lights up, that's your drain. Alternatively, as URDADDY said, pull the negative side of the battery terminal, and put the test light between the cable and the battery terminal. Start pulling fuses till the light goes out. If it lights up the test light, it will drain the battery. I spent hours tracking down a problem on my first car - finally figured out it was a faulty switch on the glovebox light. Couldn't see the light on with the door closed, but was able to track it down with the test light. Good luck.