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As mentioned, check all mechanical, electric connections (12V & 120V), and plumbing.
Also check for any signs of outer wall surface delimitation, this would represent moisture intrusion within the outer bonded wall panel layers. Also check interior walls/ceiling for surface 'dimpling', also a sign of moisture intrusion.
Jayco during the model years of 2004 into 2007 had issues with some of the roof/wall joints in conjunction with the TPO roofing material (been there, done that w/2005 Eagle). Insure sealant integrity along the roof gutter rails, and front cap/rear wall joints @ roof.
2016 GM 2500HD 6.0L/4.10
2018 Jay Flight 24RBS
2002 GM 2500HD 6.0L/4:10 (retired)
2005 Jayco Eagle 278FBS (retired)
1999 Jayco Eagle 246FB (retired)
Reese HP Dual Cam (Strait-Line)