2007 Safari Fuse #2 Blowing

[uknunn]

I have a 2007 Airstream Safari. I have the Parallax 7300 Series converter. I just picked up the trailer used this week. I love it.
My #2 yellow 20 amp fuse keeps blowing.

FURNACE-
EXT LTS-
FRT. CEILING LTS-
FLASH LT.

Any suggestions where the short may be? I have 9 ceiling lights. 2 exterior lights, and what’s the Flash light? Where do I look on the furnace?

Any help appreciated..!!