2001 INFINITI QX4 fuse

5 CHECK FUSE
1. Turn ignition switch ªOFFº.
2. Disconnect 7.5A fuse.
3. Check if 7.5A fuse is OK.
OK or NG
OK©GO TO 6.
NG©Replace 7.5A fuse.
6 CHECK START SIGNAL INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Disconnect ignition switch harness connector.
3. Check harness continuity between ECM terminal 42 and fuse block, ignition switch and fuse block. Refer to Wiring Dia-
gram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 8.
NG©GO TO 7.
7 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M32, F23
IFuse block (J/B) connectors M10, E3
IHarness for open or short between ignition switch and fuse
IHarness for open or short between ECM and fuse
©Repair open circuit or short to ground or short to power in harness or connectors.
8 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
START SIGNAL
Diagnostic Procedure (Cont'd)
EC-624

3 DETECT MALFUNCTIONING PART
Check the following.
IFuse block (J/B) connector M10
I15A fuse in fuse block (J/B)
IHarness connectors M1, E1
IHarness for open or short between fuse and fuel pump relay-1 and fuel pump relay-2
©Repair harness or connectors.
4 CHECK FUEL PUMP RELAY-1 POWER SUPPLY CIRCUIT-II
Check voltage between terminal 3 and ground with CONSULT-II or tester.
SEF348Z
OK or NG
OK©GO TO 8.
NG©GO TO 5.
5 CHECK FUEL PUMP RELAY-2 OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect fuel pump relay-2.
2. Check harness continuity between fuel pump relay-2 terminal 5 and fuel pump relay-1 terminal 3. Refer to Wiring Dia-
gram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 6.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
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FUEL PUMP
Diagnostic Procedure (Cont'd)
EC-629

6 CHECK FUEL PUMP RELAY POWER SUPPLY CIRCUIT-III
1. Turn ignition switch ªOFFº.
2. Disconnect fuel pump relay-2.
3. Turn ignition switch ªONº.
4. Check voltage between terminals 2, 3 and ground with CONSULT-II or tester.
SEF026Z
OK or NG
OK©GO TO 8.
NG©GO TO 7.
7 DETECT MALFUNCTIONING PART
Check the following.
I15A fuse in fusible link and relay box
IHarness for open or short between fuse and fuel pump relay-2
©Repair harness or connectors.
8 CHECK FUEL PUMP RELAY-2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between fuel pump relay-2 terminal 1 and ground.
Continuity should exist.
2. Also check harness for short to power.
OK or NG
©Repair open circuit or short to power in harness or connector.
FUEL PUMP
Diagnostic Procedure (Cont'd)
EC-630

CEL083
InspectionNBEL0007FUSENBEL0007S01IIf fuse is blown, be sure to eliminate cause of problem
before installing new fuse.
IUse fuse of specified rating. Never use fuse of more than
specified rating.
IDo not partially install fuse; always insert it into fuse
holder properly.
IRemove fuse for ªELECTRICAL PARTS (BAT)º if vehicle is
not used for a long period of time.
MEL944F
FUSIBLE LINKNBEL0007S02A melted fusible link can be detected either by visual inspection or
by feeling with finger tip. If its condition is questionable, use circuit
tester or test lamp.
CAUTION:
IIf fusible link should melt, it is possible that critical circuit
(power supply or large current carrying circuit) is shorted.
In such a case, carefully check and eliminate cause of
problem.
INever wrap outside of fusible link with vinyl tape. Impor-
tant: Never let fusible link touch any other wiring harness,
vinyl or rubber parts.
SEL109W
CIRCUIT BREAKER (PTC THERMISTOR TYPE)NBEL0007S03The PTC thermister generates heat in response to current flow.
The temperature (and resistance) of the thermister element varies
with current flow. Excessive current flow will cause the element's
temperature to rise. When the temperature reaches a specified
level, the electrical resistance will rise sharply to control the circuit
current.
Reduced current flow will cause the element to cool. Resistance
falls accordingly and normal circuit current flow is allowed to
resume.
POWER SUPPLY ROUTING
Inspection
EL-16

Component Parts and Harness Connector
Location
NBEL0159
SEL460X
System DescriptionNBEL0188The headlamp operation is controlled by the lighting switch which is built into the combination switch and
headlamp battery saver control unit. And the headlamp battery saver system is controlled by the headlamp
battery saver control unit and smart entrance control unit.
OUTLINENBEL0188S01Power is supplied at all times
Ito headlamp LH relay terminals 1 and 3
Ithrough 15A fuse (No. 60, located in the fuse and fusible link box), and
Ito headlamp LH relay terminal 6
Ithrough 20A fuse (No. 32, located in the fuse and fusible link box), and
Ito headlamp RH relay terminals 1 and 3
Ithrough 15A fuse (No. 59, located in the fuse and fusible link box), and
Ito headlamp RH relay terminal 6
Ithrough 20A fuse (No. 31, located in the fuse and fusible link box), and
Ito headlamp battery saver control unit terminal 7, and
Ito smart entrance control unit terminal 10
Ithrough 7.5A fuse [No. 24, located in the fuse block (J/B)].
When the ignition switch is in the ON or START position, power is supplied
Ito headlamp battery saver control unit terminal 1
Ithrough 10A fuse [No. 16, located in the fuse block (J/B)], and
Ito headlamp battery saver control unit terminal 10,
Ito auto light control unit terminal 1 and
Ito smart entrance control unit terminal 33
Ithrough 7.5A fuse [No. 11, located in the fuse block (J/B)].
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HEADLAMP (FOR USA) Ð XENON TYPE Ð
Component Parts and Harness Connector Location
EL-31

When the ignition switch is in the ACC or ON position, power is supplied
Ito auto light control unit terminal 2
Ithrough 10A fuse [No. 9, located in the fuse block (J/B)]
Ground is supplied
Ito headlamp battery saver control unit terminals 4 and 11
Ithrough body grounds M77 and M111, and M4,M66 and M147
Ito auto light control unit terminal 5
Ithrough body grounds M4, M66 and M147.
Power Supply to Low Beam and High BeamNBEL0188S0101When lighting switch is in 2ND or PASS position, ground is supplied
Ito headlamp relay (LH and RH) terminal 2 from headlamp battery saver control unit terminals 2 and 8
Ithrough headlamp battery saver control unit terminals 3 and 9,
Ifrom lighting switch terminal 12.
Headlamp relays (LH and RH) are energized and then power is supplied to headlamps (LH and RH).
LOW BEAM OPERATIONNBEL0188S02When the lighting switch is turned to the 2ND position and placed in LOW (ªBº) position, power is supplied
Ifrom terminal 7 of each headlamp relay
Ito terminal 3 of each headlamp
Ground is supplied
Ito terminal 4 of each headlamp
Ithrough body grounds E13 and E41.
With power and ground supplied, the headlamp(s) will illuminate.
HIGH BEAM OPERATION/FLASH-TO-PASS OPERATIONNBEL0188S03When the lighting switch is turned to the 2ND position and placed in HIGH (ªAº) position or PASS (ªCº) position,
power is supplied
Ifrom terminal 5 of headlamp LH relay
Ito terminal 1 of headlamp LH, and
Ito combination meter terminal 26 for the HIGH BEAM indicator
Ifrom terminal 5 of headlamp RH relay
Ito terminal 1 of headlamp RH.
Ground is supplied
Ito headlamp LH terminal 2
Ito combination meter terminal 27 for the HIGH BEAM indicator
Ithrough lighting switch terminals 6 and 5
Ithrough body grounds E13 and E41, and
Ito headlamp RH terminal 2
Ithrough lighting switch terminals 9 and 8
Ithrough body grounds E13 and E41.
With power and ground supplied, the high beams and the high beam indicator illuminate.
BATTERY SAVER CONTROLNBEL0188S04When the ignition switch is turned from ON (or START) to OFF (or ACC) positions while headlamps illuminate,
the RAP signal is supplied to terminal 10 of the headlamp battery saver control unit from smart entrance con-
trol unit terminal 5.
After counting 45 seconds by the RAP signal from the smart entrance control unit to headlamp battery saver
control unit, the ground supply to terminal 2 of the headlamp LH and RH relay from headlamp battery saver
control unit terminals 2 and 8 is terminated.
Then the headlamps are turned off.
The headlamps are turned off when driver or passenger side door is opened even if 45 seconds have not
passed after ignition switch is turned from ON (or START) to OFF (or ACC) positions while headlamps are
illuminated.
When the lighting switch is turned from OFF to 2ND after headlamps are turned to off by the battery saver
control, ground is supplied
HEADLAMP (FOR USA) Ð XENON TYPE Ð
System Description (Cont'd)
EL-32

Trouble DiagnosesNBEL0189WARNING:
IThe xenon headlamp has a high-tension current generating area. Be extremely careful when remov-
ing and installing. Be certain to disconnect the battery negative cable prior to removing or install-
ing.
IWhen the xenon headlamp is lit, do not touch the harness (covered with red or amber insulation),
bulb itself or the bulb socket with your bare hands.
INever service a xenon headlamp with wet hands.
IWhen checking body side harness with a circuit tester, be certain to disconnect the harness con-
nector from the xenon headlamp.
IWhen the xenon headlamp is lit, the xenon bulb must be installed in the headlamp housing. (Never
turn on xenon headlamp, if the bulb is out of the headlamp housing.)
CAUTION:
Make sure to install the bulb securely; if the xenon bulb is improperly installed in its socket, high-ten-
sion current leaks occur. This may lead to a melted bulb and/or bulb socket.
Symptom Possible cause Repair order
Neither headlamp operates. 1. 7.5A fuse
2. Headlamp relay circuit
3. Lighting switch
4. Lighting switch ground circuit
5. Headlamp battery saver control
unit1. Check 7.5A fuse [No. 24, located in fuse block
(J/B)].
Verify battery positive voltage is present at terminal
7 of headlamp battery saver control unit.
2. Check between battery saver control unit and head-
lamp relays (LH and RH).
3. Check Lighting switch.
4. Check harness between lighting switch terminal 8
and ground.
5. Check headlamp battery saver control unit.
Headlamp LH (low and high beam)
does not operate, but headlamp
RH (low and high beam) does
operate.1. 15A fuse
2. Headlamp LH relay
3. Headlamp LH relay circuit1. Check 15A fuse (No. 60, located in fusible link and
fuse box). Verify battery positive voltage is present
at terminals 1 and 3 of headlamp LH relay.
2. Check headlamp LH relay.
3. Check harness between headlamp LH relay and
headlamp battery saver control unit.
Headlamp RH (low and high beam)
does not operate, but headlamp LH
(low and high beam) does operate.1. 15A fuse
2. Headlamp RH relay
3. Headlamp RH relay circuit1. Check 15A fuse (No. 59, located in fusible link and
fuse box). Verify battery positive voltage is present
at terminals 1 and 3 of headlamp RH relay.
2. Check headlamp RH relay.
3. Check harness between headlamp RH relay and
headlamp battery saver control unit.
LH high beam does not operate,
but LH low beam operates.1. Bulb
2. Headlamp LH relay
3. Open in the LH high beams cir-
cuit
4. Lighting switch
5. Lighting switch ground circuit1. Check bulb.
2. Check headlamp LH relay.
3. Check the following.
a. Harness between headlamp LH relay terminal 5 and
headlamp LH for open circuit.
b. Harness between headlamp LH and lighting switch
for open circuit.
4. Check lighting switch.
5. Check harness between lighting switch and ground.
HEADLAMP (FOR USA) Ð XENON TYPE Ð
Trouble Diagnoses
EL-40

Symptom Possible cause Repair order
LH low beam does not operate, but
LH high beam operates.1. 20A fuse
2. Headlamp LH relay
3. Open in the LH low beam circuit
4. LH low beam ground circuit
5. Xenon bulb
6. HID control unit
7. Booster1. Check 20A fuse (No. 32, located in fusible link and
fuse box). Verify battery positive voltage is present
at terminal 6 of headlamp LH relay.
2. Check headlamp LH relay
3. Check harness between headlamp LH relay terminal
7 and headlamp LH for open circuit.
4. Check harness between headlamp LH and ground.
5. Replace the xenon bulb with other side bulb or new
one. (If headlamps illuminate correctly, replace the
bulb.)
6. Replace the HID control unit with other side control
unit or new one. (If headlamps illuminate correctly,
replace the control unit.)
7. Replace booster as a headlamp assembly.
RH high beam does not operate,
but RH low beam operates.1. Bulb
2. Headlamp RH relay
3. Open in the RH high beams
circuit
4. Lighting switch1. Check bulb.
2. Check headlamp RH relay.
3. Check the following.
a. Harness between headlamp RH relay terminal 5 and
headlamp RH for open circuit
b. Harness between headlamp RH and lighting switch
for open circuit
4. Check lighting switch.
RH low beam does not operate,
but RH high beam operates.1. 20A fuse
2. Headlamp RH relay
3. Open in the RH low beam cir-
cuit
4. RH low beam ground circuit
5. Xenon bulb
6. HID control unit
7. Booster1. Check 20A fuse (No. 31 located in fusible link and
fuse box). Verify battery positive voltage is present
at terminal 6 of headlamp RH relay.
2. Check headlamp RH relay
3. Check harness between headlamp RH relay termi-
nal 7 and headlamp RH for open circuit.
4. Check harness between headlamp RH and ground.
5. Replace the xenon bulb with other side bulb or new
one. (If headlamps illuminate correctly, replace the
bulb.)
6. Replace the HID control unit with other side control
unit or new one. (If headlamps illuminate correctly,
replace the control unit.)
7. Replace booster as a headlamp assembly.
High beam indicator does not work. 1. Bulb
2. Open in high beam circuit1. Check bulb in combination meter.
2. Check the following.
a. Harness between headlamp LH relay and combina-
tion meter for an open circuit
b. Harness between high beam indicator and lighting
switch
Battery saver control does not
operate properly.1. RAP signal circuit
2. Door switch LH or RH circuit
3. Lighting switch circuit
4. Headlamp battery saver control
unit
5. Smart entrance control unit1. Check harness between headlamp battery saver
control unit terminal 10 and smart entrance control
unit terminal 5 for open or short circuit.
2. Check the following.
a. Harness between smart entrance control unit and
LH or RH door switch for open or short circuit.
b. LH or RH door switch ground circuit.
c. LH or RH door switch.
3. Check the following.
a. Harness between headlamp battery saver control
unit terminals 5 or 13 and lighting switch terminal 11
for open or short circuit.
b. Harness between lighting switch terminal 5 and
ground.
c. Lighting switch.
4. Check headlamp battery saver control unit.
5. Check smart entrance control unit. (EL-324)
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HEADLAMP (FOR USA) Ð XENON TYPE Ð
Trouble Diagnoses (Cont'd)
EL-41