I think it could be the ignition relay.
I copied this statement from a post by Wolfe10 from April 2008
"Many coaches use an ignition relay so all things that work only when the ignition is on do not have to run through the ignition switch. They are a failure item."
I suggest you find the relays and try swapping them if they are all the same number. (They were the same number on my 2000 Freightliner).
My relays/fuses were in a storage bay below the drivers' feet, and Freightliner put relays and fuses in the same box.
You can also get help from the Freightliner help desk (free). 1 800 FTL HELP
Have the last 6 digits of your vin number when you call. They can read your coach's wiring diagrams and suggest common points of failure.
Fred
