Mystery Crack In Rear Outer Wall of My Cougar

There is a bondo product called Bondo Hair. It's bondo with fiberglas threads in it to help the material attach to the fiberglas around the hole. It can be sanded smooth.

Or just fill the hole with silicon chaulk and place a round reflector over the hole. Also a small vent cover will work. So far, I have repaired two holes this way and it works great. Added safety due to the extra reflectors...LOL.