I've found there are some things in an RV that dealers just don't know anything about. Stereo systems are a good example. I had sub woofer problems, also, the dealer nor Airstream could address. The person who finally fixed it was a young stereo buff with a similar system in his Airstream.
'64 Bambi II, '10 Flying Cloud FB
'05 GMC Pickup, '11 Touareg TDI
Santana tandem bike
WBCCI # 4181 VAC member