Diagnostic Procedure For A/C System

SYMPTOM: A/C system does not come on.

Fig 1: Checking A/C Auto Amp. Circuit

Courtesy of NISSAN NORTH AMERICA, INC.

1. CHECK POWER SUPPLY CIRCUITS FOR A/C AUTO AMP. 
   1. Turn ignition switch ON.
   2. Check voltage between A/C auto amp. harness connector M49 (B) terminal 15 and M50 (A) terminal 27, and ground.

      Terminals			Ignition switch position
      (+)		(-)	OFF	ACC	ON
      A/C auto amp. connector	Terminal No.
      M49	15	Ground	Approx. 0V	Approx. 0V	Battery voltage
      M50	27		Battery voltage	Battery voltage	Battery voltage

      Fig 2: Checking Voltage Between A/C Auto Amp. Connector M49 Terminal 15, M50 Terminal 27 And Ground

      Courtesy of NISSAN NORTH AMERICA, INC.

      Is the inspection result normal? 

      YES: GO TO 2.

      NO: Check 10A fuses [Nos. 8 and 19, located in the fuse block (J/B)]. Refer to "TERMINAL ARRANGEMENT ".

      • 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.
2. CHECK GROUND CIRCUIT FOR A/C AUTO AMP. 
   1. Turn ignition switch OFF.
   2. Disconnect A/C auto amp. connectors.
   3. Check continuity between A/C auto amp. harness connector M50 terminal 36 and ground.

      36 - Ground: Continuity should exist. 

      Fig 3: Checking Continuity Between A/C Auto Amp. Harness Connector M50 Terminal 36 And Ground

      Courtesy of NISSAN NORTH AMERICA, INC.

      Is the inspection result normal? 

      YES: Replace A/C auto amp. Refer to "REMOVAL AND INSTALLATION ".

      NO: Repair harness or connector.