Diagnosis Procedure

WARNING: This page is about a different car, the 2016 Infiniti QX70. However, it is still accessible from the selected car via links, so may be relevant.

PERFORM SELF - DIAGNOSIS

Perform self - diagnosis function STEP - 4. Refer to DIAGNOSIS DESCRIPTION (WITHOUT ACCS) or DIAGNOSIS DESCRIPTION (WITH ACCS).

Code No.	41	42	43	44	45	46
Blower motor duty ratio	37%	91%	65%			91%

Does blower motor speed change according to each code No.?

YES

INSPECTION END

GO TO STEP 2 .

CHECK POWER SUPPLY FOR BLOWER MOTOR

Disconnect blower motor connector.
Turn ignition switch ON.

Check voltage between blower motor harness connector and ground.

(+)		(-)	Voltage
Blower motor		-
Connector	Terminal	-
M109	1	Ground	Battery voltage

Is the inspection result normal?

YES

GO TO STEP 3 .

GO TO STEP 6 .

CHECK BLOWER MOTOR GROUND CIRCUIT

Turn ignition switch OFF.

Check continuity between blower motor harness connector and ground.

Blower motor		-		Continuity
Connector	Terminal	-		Continuity
M109	3	Ground		Existed

Is the inspection result normal?

YES

GO TO STEP 4 .

Repair harness or connector.

CHECK CIRCUIT CONTINUITY BETWEEN BLOWER MOTOR AND UNIFIED METER AND A/C AMP.

Disconnect unified meter and A/C amp. connector.

Check continuity between blower motor harness connector and unified meter and A/C amp. harness connector.

Blower motor		Unified meter and A/C amp.		Continuity
Connector	Terminal	Connector	Terminal	Continuity
M109	2	M66	38	Existed

Check continuity between blower motor harness connector and ground.

Blower motor		-		Continuity
Connector	Terminal	-		Continuity
M109	2	ground		Not existed

Is the inspection result normal?

YES

GO TO STEP 5 .

Repair harness or connector.

CHECK UNIFIED METER AND A/C AMP. OUTPUT SIGNAL

Reconnect blower motor connector and unified meter and A/C amp. connector.
Turn ignition switch ON.
Set MODE switch to VENT position.

Change fan speed from Lo to Hi, and check duty ratios between blower motor harness connector and ground by using an oscilloscope. Normal terminal 2 drive signal duty ratios are shown in the table below.

Courtesy of NISSAN NORTH AMERICA, INC.

Is the inspection result normal?

YES

Replace blower motor after confirming the fan air flow does not change.

Replace unified meter and A/C amp.

CHECK POWER VOLTAGE OF BLOWER RELAY

Turn ignition switch OFF.
Remove blower relay. Refer to FUSE, CONNECTOR AND TERMINAL ARRANGEMENT .
Turn ignition switch ON.
Check the voltage between blower relay fuse block terminals and ground. Refer to DESCRIPTION for relay terminal assignment.

(+)	(-)	Voltage
Blower relay	-	Voltage
1	Ground	Battery voltage
3	Ground	Battery voltage

Is the inspection result normal?

YES

GO TO STEP 7 .

Check ignition power supply circuit. Refer to WIRING DIAGRAM - IGNITION POWER SUPPLY - .

CHECK BLOWER RELAY
1. Turn ignition switch OFF.
2. Install blower relay. Refer to FUSE, CONNECTOR AND TERMINAL ARRANGEMENT .
3. Check operation sound of the blower relay after switching ignition switch ON.
Is the inspection result normal?

YES

GO TO STEP 8 .

NO

Replace blower relay.

CHECK FUSE

Check fuse 15A [Nos. 21 and 22, located in the fuse block (J/B)]. Refer to FUSE, CONNECTOR AND TERMINAL ARRANGEMENT .

Is the inspection result normal?

YES

Repair harness or connector.

NO

Be sure to eliminate cause of malfunction before installing new fuse.