Wiring Damage

Already repaired it with wire and and some splices. Whatever it is it must be working now... lol..

Looks like an add-on. Unless you need it, consider just removing it.

I am the third owner of this vehicle and do not have a lot of documentation. But, a block heater makes sense.

That looks like an AC power cord. Do you have a block heater or something else in that area that runs on 120 VAC?

Curious, is that what looks to be plastic wire loom wrapped with copper braid and aluminum foil? Seems like chassis wiring versus anything to do with the RV side

One broken wire up by that brake hose or whatever that rubber to metal hose is.

You are not looking at the problem correctly. See the copper wire splayed out. If you look closely at the picture, it used to have insulation on it and it connected to the wire at the top right that appears to be cut. It is 14 gage wire almost like a lamp cord..

Where does it go?

This looks like it might be heavier gauge than your typical vehicle accessory wiring, so I might venture to guess it could possibly be part of the battery combiner circuitry to charge the house battery from the engine.

It's not too surprising that it seems to be working since the conductors are still continuous. Shorting out could be a definite possibility.

To me, it looks like a squirrel did the damage, not the dog. Had the same thing happen to our car when we accidently locked a squirrel in the garage.