I have a 2008 Skyline 1811-B Layton travel trailer with a 12vdc issue on the negative circuit. After ground/neg wire leaves the battery it goes into the frame/under the trailer and comes up and connects to the power center. Except the circuit is broken somewhere under the frame so no ground actually 'connects' at the power center. The under frame wiring is hidden behind the coroplast cover with about 1000 screws. Suggestions? The +/hot circuit is good (shows 12.7 vdc and continuity), batteries are fully charged, everything runs fine under shore power. Also, I've been able to temp. fix and complete the ground circuit by running a wire on the exterior from the battery ground/neg to the power center. Separately, I did a test fix by running a wire from the battery ground/neg to the ground return leg which connects to the frame near the battery. My supposedly knowledgeable friends tell me to just add the jumper from the battery neg to the return leg and not worry about it. Its my first trailer and I'm just smart enough to know I don't know much and don't want to do anything dangerous. I really don't want to pull down the coroplast or cut a bunch of access holes if I don't need to. Thanks to all you pros in advance for your feedback!