Shouldn't need to merge any wires. If you pull off the camshaft pulley, you'll see the sensor on the JDM motor/the other "half" of the sensor on the USDM. Just swap what's on the USDM motor onto the JDM, it's a direct fit IIRC. The key here is removing that camshaft pulley.

BTW...it's the Camshaft Position/Top Dead Center sensor.