In our 05 Patriot, solar connects to the main battery bus in the rear run bay, above the battery tray. Might be yours is different. The solar controller is a small black box that is mounted to the ceiling of the 'hidden' compartment, passenger side, just forward of the rear axle. Might be easiest to check for voltage there.
Don't know your experience with solar, but if yours is the factory 100 watt panel, it will produce about 5 amps in full sun. So its really a 5 amp trickle charger. And if its cloudy.......