wayne and sherry
Being a chicken about wiring is a good thing to admit before diving in. That being said, the power you're looking for with this fantastic fan will be 12 volt as opposed to 110 volt which could hurt you more.
Schematics for wiring details in the RV are pitiful at best, and that's common across the industry. Hopefully, after you remove the plastic trim collar around the vent you already have, you may find the manufacturer already has run wiring to this area for the very thing you're trying to do............they were there in our Georgetown kitchen area. I also upgraded the existing fan unit in our bathroom, so the wiring was already there.
To determine + from -, a continuity tester will let you know what the - lead is when you touch the other end to a known ground. The color code in our rig was brown was + (12V) and white was - (grd). Doesn't' mean that's the way for everyone so check it out.
Ken and Terry
2010 Georgetown 330TS being pushed by our
2017 GMC Terrain toad (4 wheels down)