Diagnosis Procedure

1. Turn ignition switch OFF.
2. Check 30A fuse (No. 57).
   NOTE: Refer to (Fuse, Fusible Link And Relay Box).

Is the inspection result normal?

YES

GO TO 2 .

NO

Replace the blown fuse after repairing the affected circuit if a fuse is blown.

1. Disconnect rear blower motor connector.
2. Turn ignition switch ON.
3. Check voltage between rear blower motor harness connector and ground.

   +		-	Voltage (Approx.)
   Rear blower motor
   Connector	Terminal
   B21	1	Ground	Battery voltage

Is the inspection result normal?

YES

GO TO 3 .

NO

GO TO 6 .

1. Turn ignition switch OFF.
2. Check continuity between rear blower motor harness connector and ground.

   Rear blower motor		-	Continuity
   Connector	Terminal
   B21	3	Ground	Yes

Is the inspection result normal?

YES

GO TO 4 .

NO

Repair harness or connector.

1. Disconnect front air control connector.
2. Check continuity between rear blower motor harness connector and front air control connector.

   Rear blower motor		Front air control		Continuity
   Connector	Terminal	Connector	Terminal
   B21	2	M56	33	Yes

Is the inspection result normal?

YES

GO TO 5 .

NO

Repair harness or connector.

1. Reconnect rear blower motor connector and front air control connector.
2. Turn ignition switch ON.
3. Change rear fan speed from Lo to Hi, and check duty ratios between rear blower motor harness connector and ground by using an oscilloscope.
   NOTE: Calculate drive signal duty ratio as shown in the figure.

   T2 = Approx. 1.6 ms

   Courtesy of NISSAN NORTH AMERICA, INC.

   Rear blower motor		Condition	Duty ratio (Approx.)
   Connector	Terminal	Fan speed
   B21	2	1st	25 %
   		2nd	33 %
   		3rd	41 %
   		4th	51 %
   		5th	61 %
   		6th	69 %
   		7th	81 %

Is the inspection result normal?

YES

Replace rear blower motor. Refer to Removal and Installation - Rear Blower Motor (If Equipped) .

NO

Replace front air control. Refer to Removal and Installation - Front Air Control .

1. Turn ignition switch OFF.
2. Disconnect rear blower motor relay connector.
3. Check continuity between rear blower motor relay harness connector and rear blower motor harness connector.

   Rear blower motor relay		Rear blower motor		Continuity
   Connector	Terminal	Connector	Terminal
   M59	3	B21	1	Yes
   	6

Is the inspection result normal?

YES

GO TO 7 .

NO

Repair harness or connector.

Check continuity between rear blower motor relay harness connector and ground.

Is the inspection result normal?

YES

GO TO 8 .

NO

Repair harness or connector.

Check rear blower motor relay. Refer to Component Inspection (Rear Blower Motor Relay) .

Is the inspection result normal?

YES

Check rear blower motor relay power supply circuit. Refer to (Battery Power Supply) and (Ignition Power Supply).

NO

Replace rear blower motor relay.