Might need to provide some more details on that. Since I was just troubleshooting a similar issue, I thought I would respond to give you some ideas. I have 16BHS equipped with a Furrion DV7200 A/V system. I assumed that the HDMI input on the front of the unit was simply a pass-thru to two other HDMI interface ports I have near two different TV mounting areas. This past weekend I tested with a standard DVD player connected. On the TV, with all equipment powered and cables connected, I saw the dreaded "no signal" message displayed. So I accessed the rear of the Furrion unit and disconnected the 2nd HDMI connection for the outdoor TV mount. Once I did that, the message goes away and I was able to see a little flicker of the movie I was testing with. But still not completely working and also no audio. Furrion unit mode was set to "HDMI". Can't think of much else other than that which would need to be configured from default. I also did test the DVD player connected directly to the TV and that worked as expected (confirms no issues with DVD player or TV). I recently posted this issue in a Wolf Pup FB group as well, and someone hinted that the Furrion units aren't very sophisticated so it just simply may not work properly. But someone else suggested turning off the TV antenna amplifier which I did NOT think of/try and will re-test at some point to see if it has any effect. But I really don't see how that would impact anything since they are two separate interfaces (i.e. COAX vs. HDMI).
Plan B would be to continue connecting the multimedia source (e.g. DVD, Roku, etc.) direct to the TV and then link to the Furrion unit using Bluetooth to get the audio over the speaker system. Which was ultimately my goal.