Okay everybody, I need your help. I have a 1991 Viking 180. I have a few issues that I think are adding up to a pretty major overhaul of the 12v wiring, but with no wiring diagrams available from the manufacturer (too old) I need any help you folks can offer. Please note my electrical knowledge is pretty limited (I have a couple friends who know what they're doing teaching me). The only 12v we had when we got it was the two ceiling lights and the outside light. Making things more complicated: the PO clearly did a rewire at some point (along with a lot of other questionable remodeling I've been correcting) and no wire colors match properly. For example, the connection to the battery is black: positive and white: negative. Issues: 1) We recently installed a switch panel running 4 USB ports and 2 cig sockets. Connected into the 12v line coming out of the converter. My plan was to run a small (400W) inverter from one of the cig sockets just to power a box fan at night and other occasional AC needs. However, we aren't getting enough juice through the inverter to power the box fan. We then attached the inverter directly to the battery via alligator clips and got plenty of power. Attached it to the spot where we wired in the switch panel by the converter, very low juice again. DID NOT try to connect to the wiring before the converter. The current wiring is pretty thin wire. It looks 14 gauge or at max 12 to me. Could this issue be caused by insufficient wire capacity? Or could the converter somehow be impeding the flow of 12v? 2) I have the fairly common issue of tail lights dimming when braking with TV headlights on. I know the common solution to this issue is a loose/dirty/bad ground, but is there some place specific I should start looking? I had the back end off and the PO made spaghetti back there with multiple connector clips between wires for no apparent reason. 3) On the back of my converter where the 12v wiring comes out, there's a single wire (it's blue but no idea if that's original or not) that leads nowhere. Jut has a cap taped on it, not connected to anything. Any guesses as to what this is? I would really appreciate insight into my specific issues, any wiring diagrams either standard or brand/model specific, etc. If it comes to a full re-wire, I feel like I can't just recreate what the PO did with better gauge wire because I have no idea what they did/didn't bypass. Ideally I want to add a second battery in parallel, solar, and electric brakes, but I'm just not sure if the current wiring setup is good enough to do that. Thanks for the help.