this relay is for what??

I did the same but with a 73 duster and 74 Valiant harness same problem no juice to the ignition the black wire at the bottom ground it then it should have juice. the other I thought they were the backup lights and go to the tranny maybe thats why they dont work lol going to look at that now new tranny harness new switch dont work! maybe because they are hooked to my seat belt should do up the belts and the backup lights may come on lol I hope I am not that stupid but maybe
whew that was close still dont work tho