I am having exactly the same problem, and I have a call in to Cummins Onan Tech Support for two days, no answer. The backlight is on, but no text is displayed. Did they replace your board at no charge?
I have had no such problem with the battery disconnect, relays, or fuses. I have no idea why the text is no longer displayed.
2006 Jayco Seneca 34SS
2006 Jeep Wrangler Unlimited Rubicon Toad