Hello, I'm about to wire a friends 1929 Tudor headlights which are 3 prong sealed beams. It has the stock light switch with 3 wires going to each headlight. As I understand the sealed beams have prongs for high, low and ground. The 3 wires coming from the light switch are high, low and parking. What is the correct way to wire the sealed beam headlights in the absence of a parking light? Do the sealed beams get grounded somewhere? Thanks.