Buying a Former Rental Class C. How many of us out there?

General question about solar on these ex-CA rentals. I read some of the earlier posts on solar. On the Coach I'm in the process of purchasing, I'm being told that the solar cell is in place but the charging light will not indicate something is working on the panel. Assuming the worst, is the cell on these a generic unit I can be procured easily? My first angle will be to get CA to fix whatever the issue is prior to delivery.