Mine blew a fuse last year. I replaced it, and it blew again when I tried to turn it on under gas. When I opened the cover outside, I noticed that some of the wires had melted as a result of a flare up caused by a spider nest in the gas tube.
Have you opened it up to inspect everything outside?
2013 Silverado 2500HD LTZ CC 6.6L Duramax Diesel
2014 Sunset Trail SF270BH
Holly & Buster, mini Dachshunds
2016: 1 trip, 3 nights in 1 state, 316 miles
2015: 5 trips, 18 nights in 3 states, 2707 miles
2014: 5 trips, 14 nights in 3 states, 2426 miles