Tara,
We have a couple of those big guys that use the big square batteries (this is my thing left over from tenting days). Of course the batteries are expensive and just when you need it, it is dead. It was one of those things that wasn't real high on our list and at first we couldn't figure out why it wasn't working. Then I found the umhooked wire. So now all is well and we just have to remember to take it out if we are not hooked up.
Happy trails...........................
Sue and Ed Rowe
Hemet California
2005 3400RL
2006 GMC 3500 Dually, D/A, Crew Cab, Long Bed