So I have a 1983 fox that was a 4cyl auto and is now a 302 manual that I picked up from a guy and in my interior there’s some wires dangling in driver footwell that look important with a big plug coming off them attached to a black box. I have no turn signals, gauge lights, or working sound fr radio and I’m wondering if anyone knows what this plug is or where it plugs in. There’s no obvious spot under dash.