this relay is for what??

That mess of cable ends under that rusted nut is a mess I do plan to fix. I sold this car 10 years ago and bought it back. I was in the process of tearing it apart back then- when I had a garage. Now-no garage- so trying to get it to run. Had to get another wiring harness out of a dart and doing this in a crunch time. One of those- lets get it running- then make it nice deals. I got her running, but need to get some of these issues figured out and nicer weather. Right now- I cant5 seem to use the ign switch-wont do anything- so maybe as said above-starter relay- will fix that. Then off to get better grounds behind dash. I did the rewire for a high output alt already also. I didnt have the dash, windshield, and half the wiring in it for 10+years. Going by help here and what I remember where things went. It helped last year when I had a 75 duster sitting right next to it-its sold now.