We have factory solar on our 1998, the wires behind the fridge go to the solar control panel, which would be mounted on the panel on the side of the sink, next to the door. The wires to the solar panels go up through the fridge roof vent to the roof. I bet if you look under your sink, you will find the other end of the wires. And I believe the wire location is also in the owners manual. Our solar panels still work great, there are smarter computer controllers now, but I have not seen the need to upgrade.