ELECTRONICS L300

Hello, I need the help of a Mitsubishi L300 “Electronics connoisseur”; and that is that since a radio change, the “cockpit lighting” doesn’t work anymore– there is extra security for this eventl.ne or did I cut through the ground cable (are they hanging together at all?) In any case, it’s pretty stupid to drive in the dark at this time of year; I thank you in advance for help and tips.