You'll need to drop the coroplast and go at it from the bottom to get to the valve. I'm not familiar with an 05, but on later models you can take the basement wall off to access where the cable connects to the handle. Some of the handles also have a screw that goes into the middle of the handle to hold it on.
Dick, Joyce, Diego, Picatso and Gustav
2017 3720 RL, MorRyde pin box
2017 3500 Dodge Maxi DRW 4X4, Pullrite Hitch, IS, Disk Brakes, 3rd AC, Winegard Traveler, Bathroom door mod, Dometic 320, couch for desk swap, etc.