Just thought of something else. It looks like the fuse on the left is the battery positive and the fuse on the right is the converter positive, or vice versa. What are the value of those fuses? The depending on the model, the converter could source as much as 60 amps. Depending on the battery or batteries, more than 30 amps in the negative lead could be normal.
“You cannot reason someone out of a position they have not been reasoned into"
Al, K5TAN and Missy, N4RGO WBCCI 1322
2002 Classic 30 Slideout -S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins