89' W100 Radio wiring.

My W100 RC's radio wiring is cobbled from years of owners. I ordered full on service manual so I can have wire diagrams. In the mean time I need some help identifying some plugs and what might be missing. I have square-ish black plug that has gray, black, pink and red wires. Red, gray and pink are cut off the plug. No factory speaker wires to be found. Some lamp cord speaker wire going to rear 6x9's. I also have a extra 194 lamp & plug that I don't know where it goes (ash tray?). It lights and dims with head light switch and a 2 wire gray plug just hanging out. On the black plug the gray and red wire never have power on them, pink has 12.7 constant power. I found a light gage orange wire that seems to have ignition power just hanging out under the dash. Any help would be great.