3. Detect Malfunctioning Part

WARNING: This page is about a different car, the 2004 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.

Check the following.

Harness connectors M71, F59
Combination switch (spiral cable)
Harness for open and short between ECM and combination switch
Harness for open and short between TCM and combination switch
1. Repair open circuit or short to ground or short to power in harness or connectors.