Second Position Switch: Description
WARNING: This page is about a different car, the 2004 Nissan Murano. However, it is still accessible from the selected car via links, so may be relevant.
Second position switch is built into CVT control device.
When selector lever is in "S" or "L" positions, second position switch turns ON and sends a signal to unified meter and A/C amp.
Then signal is transferred to TCM with CAN communications to improve engine brake performance.