I just bought a 1999 Holiday Rambler Endeavor diesel pusher. I am getting the same beeping as described above. I have also removed the the air brake switch h that is next to the electronic drive control. I did not find an electrical switch attached to the air Intake air switch. I think I'm also getting a code when I press the up and down on the controller. It is reading, L--7. Any help would be very helpful,
Thanks
Steve