Diagnosis Procedure

WARNING: This page is about a different car, the 2018 Nissan Titan XD and 2018 Nissan Titan. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FUSE
1. Turn ignition switch OFF.
2. Check 50A fuses (No. S, V and Z, located in relay box).
  NOTE: Refer to the appropriate system Terminal Arrangement .
Is the inspection result normal?

YES

GO TO 2 .

NO

Replace the blown fuse after repairing the affected circuit.

CHECK POWER SUPPLY CIRCUIT

Turn ignition switch ON.

Check voltage between PTC heater connector and ground.

Terminals			Condition of PTC heater	Voltage (Approx.)
(+)		(-)
PTC heater connector	Terminal
E78	1	Ground	ON	Battery voltage
			OFF	0 V
	3		ON	Battery voltage
			OFF	0 V
	5		ON	Battery voltage
			OFF	0 V

Is the inspection result normal?

YES

GO TO 3 .

GO TO 4.

CHECK GROUND CIRCUIT

Turn ignition switch OFF.
Disconnect PTC heater connector.

Check continuity between PTC heater connector and ground.

PTC heater connector	Terminal	Ground	Continuity
E78	2		Yes
	4

Is the inspection result normal?

YES

Replace PTC heater. Refer to Removal and Installation .

Repair or replace harness.

CHECK HARNESS CONTINUITY

Disconnect PTC relay connectors.

Check continuity between PTC heater connector and PTC relay connector.

PTC heater connector	Terminal	PTC heater relay connector	Terminal	Continuity
E78	1	E144	5	Yes
	3	E146
	5	E145

Check continuity between PTC heater connector and ground.

PTC heater connector	Terminal	Ground	Continuity
E78	1		No
	3
	5

Is the inspection result normal?

YES

Check intermittent incident. Refer to Intermittent Incident .

Replace or repair harness.