WHICH LED TURN SIGNAL KIT DO I NEED? Harley Davidson motorcycles come with one of two styles of rear LED turn signals, 1156 Single Contact and 1157 Double Contact. If you have a center rear tail light, you will need the 1156 kit. It has 1156 rears that function solely as turn signals. If you do NOT have a rear center tail light, you will need our 1157 turn signal kit.