4-Way Connector
PIN #1 - covered in plastic on trailer end - (female) -- Ground --------------- sometimes white PIN #2 - exposed metal on trailer end ------ (male) ---- Tail Lights ---------- sometimes brown, black PIN #3 - exposed metal on trailer end ------ (male) ---- Left Turn & Brakes --- sometimes yellow PIN #4 - exposed metal on trailer end ------ (male) ---- Right Turn & Brakes -- sometimes green