here is the photo. If your Vanner is located where ours is, you can see the 3 Prevost breakers above it. Trip the "red buttons" and you will effectively cut the 12 volt trickle the DDEC and ATEC take from the 12 volt side of the chassis batteries. We have found both on our last coach, 2002 XLII Marathon 1 slide, and this coach, it takes about 3 weeks for the DDEC and ATEC to drain the batteries to the point where the imbalance is so great in all four batteries that the coach won't start. When you turn on your ignition key, and the dash is dark, " no icons/idiot lights are on, your flat, requiring using the "converter's jump button, or getting out the 24 volt charger.. Hope this helps.