This is very helpful!Hi @Crux
Typically a scorched connector means a problem with the female connector's contact to the male tab. The connector could have been malformed and too loose or perhaps bent during install and didn't make adequate contact with the tab.
The fridge still working with a blown fuse is the troubling part. I believe these fridges only have one pair of inbound conductors and all fridge load (compressor, light) draw from there. Something could be mislabeled (the fuse block). Or the fuse blew after the last time your fridge had power. Test both sides (positive probe of a multimeter) of the fuse block (and negative probe grounded, of course) and see where you have power. Repeat both with and without a working fuse in place. Of those four scenarios, you'll have 12v power before the fuse now matter what. You'll only have power after the fuse if a good fuse is in place. If you have power after the fuse slot with a blown fuse or no fuse, something is dangerously wrong with that fuse block and needs further investigation and likely replacement of the fuse block.
You may want to temporarily wire up the fridge without re-installing just to ensure it functions properly before you go through the trouble of permanently wiring and reinstalling.
Review the Dometic owner's manual for your specific fridge. It will say max load of the fridge and so will the fridge label inside the fridge. You'll be able to figure out the appropriate conductor size for the load and conductor length (the length of the loop, positive and negative, from the fuse block to the fridge, which is likely rather short). These don't draw much. Probably only a max of 3 or 4 amps on 12v. Maybe 5amps on startup. Conductor size can be fairly small and still be adequate and there is no value in wiring in larger-than-needed conductors.
A fuse needs to be sized to protect the smallest gauge wire in the entire run. Don't upsize the fuse as you are not changing the wiring inside the fridge housing and upsizing the fuse may mean your fuse will take higher amps than some wire somewhere in the path.
I tested the power on both sides of the fuse slot. Everything looks good.
I replaced with new much longer wires wrapped in a loom so I can easily pull out the fridge if needed in the future along with the same 15 amp fuse.
I think the problem was the female spade connector that plugged into the back of the fridge.
Over time (4 wheeling), this connection must have loosened and then caused a short.
The new spade connector is very tight.
Should be all good now. *crossing fingers*