power to video switch

Yes, lack of power would effect antenna booster. No power to booster.
Look in exterior bin below the driver's seat area for fuses.

You'll need to find a 12V supply for the switch because w/o power the "booster" function of the switch will not work and you will probably get poor TV reception.

Read the manual (PDF).

Have, on occasion found them marked with labels like "RADIO" but to be honest.

Find the primary house fuse block, get a test lamp (This is like an ice pick with a light bulb in the translucent plastic handle and a wire with clip) clip the clip on a known ground and go tap tap on each and every fuse in the box (Tap/probe both ends one at a time)
Dark/Dark fuse unkonwn
LIGHT LIGHT fuse goood
LIGHT dark or dark LIGHT, fuse bad.

In the house block, dark dark should not happen (Does happen on the chassis block though).

Found the solution. I e-mailed Holiday Rambler. The tech told me to look for the fuse in the front bay under the driver's seat #10. Blown fuse....replaced.....four month problem resolved!!
Thanks,HR!
Gordon.

Sounds like the area I said to look!