Diagnostic Procedure For A/C System

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.

SYMPTOM: A/C system does not come on.

CHECK POWER SUPPLY CIRCUITS FOR FRONT AIR CONTROL
1. Disconnect front air control connector.
2. Check voltage between front air control harness connector M49 terminals 14 (Y/G) and 22 (Y/R), and ground.
  
  Fig 2: Front Air Control Harness Connector M49 Terminals 14, 22 And Ground Voltage Specification Chart
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Fig 3: Checking Voltage Between Front Air Control Harness Connector M49 Terminals 14, 22 And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
- OK: GO TO 2.
- NG: Check 10A fuses [Nos. 8 and 19, located in the fuse block (J/B)]. Refer to "FUSE BLOCK-JUNCTION BOX (J/B) ".
  - If fuses are OK, check harness for open circuit. Repair or replace as necessary.
  - If fuses are NG, replace fuse and check harness for short circuit. Repair or replace as necessary.
CHECK GROUND CIRCUIT FOR FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Check continuity between front air control harness connector M49 terminal 1 (B) and ground.
  - 1 - Ground: Continuity should exist.
OK or NG
- OK: Replace front air control. Refer to "FRONT AIR CONTROL ".
- NG: Repair harness or connector.
Fig 4: Checking Continuity Between Terminal 1 (B) And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.