No A/C Display is Shown

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 9 (W) and AV control unit harness connector M77 terminal 44 (W).
  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.
4. Check continuity between AV control unit harness connector M77 terminals 44 (W), 45 (B) and ground.
  1. Continuity should not exist.
Fig 1: Check Harness (No A/C Display Is Shown)
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK >> GO TO 2.

NG >>
- Check connector housings for disconnected or loose terminals.
- Repair harness or connector.
CHECK A/C-AV, 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 terminals 44 (W), 45 (B) and ground.
  1. Approx. 3.5V or more.
OK or NG

OK >> GO TO 3.

NG >> Replace A/C auto amp.
CHECK A/C-AV, 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 44 (W), 45 (B) and ground.
  1. 44 (W), 45 (B) - Ground : Refer to " TERMINALS AND REFERENCE VALUE FOR AV CONTROL UNIT "
Fig 3: Checking Voltage Signal Between AV Control Unit Harness Connector M77 & Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK >> Replace A/C auto amp.

NG >> Replace AV control unit.