John's post is exactly why I use the light to see when the power is on. I would wager three Amish Craftsmen that some rigs are wired one way and some rigs the other!
As Jimcol said, you need to check that the disconnect switch is working properly if you are sure that the DC power is not working in either position. After that, I would have to defer to more knowledgeable electrical gurus.
Bingo