Can't find location of frame crack/issue. Now what?

You'll need to remove everything under the deck so you can access the up-right members to see where it's cracked, mine was on the front ones at the top, fortunately Cedar Creek did the whole repair at their cost ( on a 10 year old fiver',that's their idea of customer service!) and after they had Lippert re-do it twice they did additional gusseting just to beef it up. a good welding shop should be able to fix that for you, good luck!

Red Green: When the going gets tough, switch to
power tools.