WARNING: This page is about a different car, the 2008 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.
Check continuity between terminals of the key switch and key lock solenoid.
CONTINUITY REFERENCE CHART
Condition
Terminal No.
Continuity
Key inserted
3 - 4
Yes
Key withdrawn
No
Fig 1: Checking Continuity Between Terminals Of Key Switch And Key Lock Solenoid