jomps

was freshening grounds and connected positive end last and didnt realize thats a nono until my blinkers quit working and did some research...so I checked fuses and I think its the flasher relay that blew....is that even possible? when I go through cluster diagnostic turn signals never flash and hazards dont work either, so I guess replace the relay and see...already did it the other month but not understanding how connecting a positive last could cause an issue like that...any input?