On our 99 Contessa Naples, the solar panel controller is located on the front vertical "firewall" under the foot of the bed, driver's side. It is a small module about 4"x5"x1", and is labeled Siemens as the manufacturer. There are also fuses associated with the solar panel located on the battery compartment wall. The set up does not match the description in our Beaver Contessa Owner's Manuals (which references two solar panels, a 100W for the house batteries, and a smaller "maintainer" panel for the chassis batteries). Our Contessa only has one 100W siemens solar panel on the roof.