A/C Operation Is Not Possible

WARNING: This page is about a different car, the 2003 Infiniti M45. However, it is still accessible from the selected car via links, so may be relevant.

CHECK HARNESS
1. Disconnect A/C auto amp. connector and AV control unit connector.
2. Check continuity between A/C auto amp. harness connector M119 terminal 10 (R) and AV control unit harness connector M77 terminal 43 (R).
  1. Continuity should exist.
3. Check continuity between A/C auto amp. harness connector M119 terminal 20 (B) and AV control unit harness connector M77 terminal 45 (B).
  1. Continuity should exist.
  Fig 1: Checking Harness (A/C Operation Is Not Possible)
  Courtesy of NISSAN MOTOR CO., U.S.A.
4. Check continuity between AV control unit harness connector M77 terminals 43 (R), 45 (B) and ground.
  1. Continuity should not exist.
OK or NG

OK >> GO TO 2.

NG >>
- Check connector housings for disconnected or loose terminals.
- Repair harness or connector.
CHECK AV-A/C, AC-CLK COMMUNICATION SIGNAL
1. Connect A/C auto amp. connector.
2. Turn ignition switch ON.
3. Check voltage between AV control unit harness connector M77 terminal 43 (R) and ground.
  1. Approx. 3.5V or more.
OK or NG

OK >> GO TO 3.

NG >> Replace A/C auto amplifier.
CHECK AV-A/C, AC-CLK COMMUNICATION SIGNAL
1. Connect AV control unit connector.
2. Turn ignition switch ON.
3. Check voltage signal between AV control unit harness connector M77 terminals 43, 45 and ground with CONSULT-II or oscilloscope.
  1. 43 (R), 45 (B) - Ground : Refer to " TERMINALS AND REFERENCE VALUE FOR AV CONTROL UNIT "
OK or NG

OK >> Replace A/C auto amp.

NG >> Replace AV control unit.