Check out the DC-Dc converter wiring for lighting and wiring for stoplights. I experienced a simillar problem on Yale ERP Spare connector on Lihting harness underneath Battery had coroded
and shorted out, I got lucky the truck went on fire while I was checking things out with a meter, Your problem sounds simillar.
Titus
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.