The front park lamp fixtures are surrounded in plastic right ? if so, There should have been a ground from those to the core support from the factory. Meaning 3 wires from each bulb socket.
Now IF... the front fixtures are metal to metal mounted like 67 Barracuda, The loss of ground in these is often the bulb base not connecting to the crusty socket its in. Or maybe the socket is loose in the pot metal housing. I saw one before with gobs of solder melted all around the bulb socket where it was factory crimped to the housing. Still little to no connection. All that was needed was to drill a tiny hole through the crimp and put a small screw through it.