I own a 1991 Sunline Solaris(2490), it has a 40amp Magnetek Model#3240. I had some power problems but was able to fix it by replacing the internal fuse on the converter. My question is this, when I thought I would have to buy a new converter, I noticed that the new one only has a "+" in and "-" in. My camper has three wires to the converter. A red,white and black. The 110volt wiring is no problem. How would I wire the DC side of the converter if it only takes two wires and my camper has three?