Back Door Power Supply and Ground Circuit Inspection

WARNING: This page is about a different car, the 2005 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.

BACK DOOR POWER SUPPLY CIRCUIT INSPECTION
1. Turn ignition switch OFF.
2. Disconnect back door control unit.
3. Check voltage between back door control unit connector B55 terminal 3 and ground.
  1. 3 (Y/R) - Ground: Approx. battery voltage
  Fig 1: Checking Voltage Between Back Door Control Unit Connector B55 Terminal 3 And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 2.
2. NG: Repair or replace harness.
BACK DOOR GROUND CIRCUIT INSPECTION
Check continuity between back door control unit connector B55 terminal 1, 2 and ground.
1. 1 (B) - Ground: Continuity should exist.
2. 2 (B) - Ground: Continuity should exist.
  
  Fig 2: Checking Continuity Between Back Door Control Unit Connector B55 Terminal 1, 2 And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: Circuit is OK.
2. NG: Repair or replace harness.