Hi there. Newbie camper owner who recently purchased an 07 Niagara and I'm currently working through some electrical issues. Kindly asking for help/advice on a few specific things: -I’m troubleshooting power issues from the battery (shore power fine but nothing on 12V) and wanting to test my fuses on the 12V side of my converter. I have a test light, my first time to use one, and my understanding is that I need to clip the cord onto a ground wire (or metal on the trailer frame?) but the cord is only 4’. What can I clip it onto for a ground? Also, should battery be connected and kill switch on, or no? -Assuming fuses check out fine (which they should because I replaced them all as part of my troubleshooting journey), what is a way to check my converter to see if it's dead? -Celing lights: I'm taking them down because I need to replace a ceiling section and there are blue connectors that seem to hold the wiring together (pic attached); are these something I can pry apart to disconnect the wires or do I need to cut the wires and where should I make the cut? 07 Niagara pics of converter and light wiring connectors are attached. TIA!