I am working on correcting a short in my accessory wiring, and while making progress I have hit a plateau.  I thought someone might have experienced this and could save me much time searching ...

The main symptom is that when I put the multimeter ground on the ground of the accessory battery, and touch the positive probe to the metal on the van, I get + 12 volts. Yes, that is a ground to ground connection producing  +12v.  I assume somewhere a positive wire is touching the van body but have not found it.  I have been isolating and testing circuits, and isolated the short down to the circuit that goes to the cigarette lighter and glove box light.  When I disconnect that circuit the symptom goes away. Neither the cig lighter or dash light work, nor do the interior lights.  Everything else works.  I traced wires and have not found a break.  I recently upgraded the dash light to a USB port and have been moving more accessories to the accessory battery, so I may have screwed something up.  It is possible that something is disconnected and touching a positive wire, or in pulling wires around I misconnected something.  I previously took the radio off of this circuit and ran a line direct to the accessory battery.  Then, as part of my diagnostic effort, I connected the wire to the cig lighter directly to the accessory fuse bus (bypassing the rat's nest behind the fuse bus).  The fault followed that line.  So, I have made progress, but at the moment I am stumped.  I should add, no fuses are blown and nothing seems to be getting hot even with the ground getting + voltage. And, isolating that circuit (to the cig lighter) did not bring back the interior lights.  I find the whole thing very strange.

Thanks in advance for any suggestions.  Ideas about further circuit testing would be especially helpful.

Dave B
Boise