The "egg shaped modules" are most likely ferrite chokes which block RF interference from traveling down the wire. They're often found on computer and video cables.
Your camera probably has 12 v power to it. Check the wires for 12 v power. You could also check the video cable with a long jumper cable to test continuity.
If the wire doesn't run the length of the RV, then perhaps it's wireless.
Best way to help troubleshoot the system would be to contact Fleetwood and see what was installed at the factory. Perhaps it's original, perhaps it's been changed.
If you've installed LED or fluorescent lights, they could cause interference if it's a wireless system.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI