Issue with turn signals in 70 Dart

They are not relays. They are "flashers." I don't know who the hell started calling them "relays." Probably the damned English. LOL

You should not be having all that much trouble. Maybe they were all bad, maybe that's why they were "laying around." No. 552 used to be my default "go to" flasher. They don't cost "all that much."