There has been several problems posted on this forum with the IRV radio. I have an IRV66 that had sound problems cutting in and out. While under warranty, I called Patrick Industries 574-970-8287. They sent me a new one which I had in 5 days. I installed it, but the cd player would not work correctly, so I called them back. They sent me a new one right away which I had in 5 days. No problems since. Easy to take out and reinstall the new one. Great customer service.
Yours might be a reception problem. You might have to pull it out and make sure the antenna is connected. First remove front face by using a screw driver on the side. You should see slots to push out. Then you will see the mounting screws which you remove and then pull out the unit. You will see the antenna plug. I would check to insure that the antenna is plugged in. Or pull out and put back in. Like I said if you have any questions call Patrick Industries at the phone number listed above. Or you can return RV to the dealer for repair and hope to get it back in a few weeks. If you are returning to dealer with a punch list, just include. The first unit I had, the FM reception was not very good. So I discussed with dealer and they said where I live reception was poor. But due to sound problems cutting out (FM, AM, CD), I called Patrick Industries and the second and third unit had very good FM reception so yours may not be location. If you have another FM radio, try it near your RV and check reception.
I did not think I had a location problem because my truck radio picked up FM so good right next to TT.
2015 Flagstaff 26VFKS
TV - 2014 F150 Crew Cab 5.0L
WDH - 1,200 Equalizer