For the 1500 type front parking lights, the dual filament bulb fits only one way. The contact plate might occasionally be reversed inside the bulb socket. That results in illumination of the high filament for parking light and low filament for turn signal. Solution is to remove the lens (twist left and pull), remove the bulb (push, twist left and pull), push wiring from back to bring the contact plate forward out of the socket, rotate contact plate 180 degrees, and reassemble everything.

1500 type dual contact front parking light and turn signal socket