Okay, you seem lost as hell so I'll help you.
First up, the S14 front turn signal uses 1156, not 1157. You can verify this by calling up an auto parts store and ask for the bulb number for a 1995+ Nissan 240SX front turn signal. The 1157 may not fit properly into the socket.
It's a little hard to see from the picture I posted, but the 1156 is a single filament while the 1157 is a dual filament. What this means is that the 1156 will only turn on at one brightness level when it's lit, and the 1156 can only be wired up to one power source.
The 1157 is like 2 bulbs in one. The 2 filaments run on separate circuits and can operate independently of each other. When only one filament is on, it's dim. When both filaments are on, it's brighter. The 1157 can operate as a parking lamp, becoming brighter with the turn signal whereas the 1156 can only be used either a parking or signal light, not both.
I suggest that you wire your signal up like the S13, where it comes on dim for parking and becoming brighter for signaling. When you hook the parking wire and signal wire together, it will not flash when the parking lamp is on and you turn on the signal because the parking lamp circuit is already providing current. I also don't believe it will become any brighter since it's already drawing current. Providing an additional current source will not make the bulb any brighter.
I will now consult the FSM and provide you with exact wire colours. Perhaps you or SimpleS14 can provide the wire colours for the JDM corner lamp?
