1. Assuming you still get the lights on the front (?)
2. Check all cables in and out. SB is fed from TV audio
3. Make sure TV isn't muted
4. Not sure about the radio...it belongs in a car, not an RV!
Failure could have happened of course. Check DC voltage to SB...fed via a "wall wart" type power supply. If no lights it may have become disconnected, etc.
The thing is an embarrassing piece of junk as far as I'm concerned. FR really scraped the bottom of the barrel for this one...barely adequate as far as I'm concerned. Hope suggestions help. Let me know.
Cedar Creek 36CKTS
F350 Lariat ("Big Blue")