Welcome to the forum, Cheno
Placing the negative battery cable on the positive post is your result.
When the person that purchased my coach had a chassis battery replaced the installer placed the negative cable on positive post to connect it permanently which burnt out control boards under dash and interior fire wall, caused the bottom of LR slide to move out because it was locked, rear camera control burn out and numerous fuses blown.
This link will show you where all your fuses will be located some may need the compartment materiel to be lifted back off Velcro flap, like in your power bay or water bay.
The link comes from
this link on your battery charging systems and maybe pictures of equipment locations. This link will have many diagrams you need that may have fuses within them.
All these links come from
this sticky covering many items in your coach.
Many of your fuses and controls which maybe burnt out maybe in a compartment accessed outside under your drivers seat location..
You didn't say where your coach is or if it was started and moved home or what ever, the process in finding everything wrong will take some time and some of the problems may not show up at this time, you need to get coach to a Newmar dealer who has experiance with this type problem.
In the second link I gave you there are some pictures of locations such as the main 12v fuse compartment I mentioned and maybe someone 2006 owner will add pictures for you of locations of defective items you have now.
Its going to be a slow process to find everything in your loaded coach.
When you have time please fill out your coach information in your signature..
Brochure ----
Owners Guide