jump start terminals INFINITI QX56 2008 Factory Service Manual

GI-42
< BASIC INSPECTION >
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
no voltage; open is between fuse block and SW1 (point A).
• Close SW1 and probe at relay. voltage; open is further down the circuit than the relay.
no voltage; open is between SW1 and relay (point B).
• Close the relay and probe at the solenoid. voltage; open is further down the circuit than the solenoid.
no voltage; open is between relay and solenoid (point C).
Any powered circuit can be diagnosed using the approach in the previous example.
TESTING FOR “SHORTS” IN THE CIRCUIT
To simplify the discussion of shorts in the system, please refer to the following schematic.
Resistance Check Method
• Disconnect the battery negative cable and remove the blown fuse.
• Disconnect all loads (SW1 open, relay disconnected and solenoid disconnected) powered through the fuse.
• Connect one probe of the DMM to the load side of the fuse terminal. Connect the other probe to a known good ground.
• With SW1 open, check for continuity. continuity; short is between fuse terminal and SW1 (point A).
no continuity; short is further down the circuit than SW1.
• Close SW1 and disconnect the relay. Put probes at the load side of fuse terminal and a known good ground. Then, check for continuity.
continuity; short is between SW1 and the relay (point B).
no continuity; short is further down the circuit than the relay.
• Close SW1 and jump the relay contacts with jumper wire. Put probes at the load side of fuse terminal and a known good ground. Then, check for continuity.
continuity; short is between relay and solenoid (point C).
no continuity; check solenoid, retrace steps.
Voltage Check Method
• Remove the blown fuse and disconnect all loads (i.e. SW1 open, relay disconnected and solenoid discon-
nected) powered through the fuse.
• Turn the ignition key to the ON or START position. Verify battery voltage at the battery + side of the fuse ter- minal (one lead on the battery + terminal side of the fuse block and one lead on a known good ground).
• With SW1 open and the DMM leads across both fuse terminals, check for voltage. voltage; short is between fuse block and SW1 (point A).
no voltage; short is further down the circuit than SW1.
• With SW1 closed, relay and solenoid disconnected and the DMM leads across both fuse terminals, check for voltage.
voltage; short is between SW1 and the relay (point B).
no voltage; short is further down the circuit than the relay.
• With SW1 closed, relay contacts jumped with fused jumper wire check for voltage. voltage; short is down the circuit of the relay or between the relay and the disconnected solenoid (point C).
no voltage; retrace steps and check power to fuse block.
GROUND INSPECTION
• Ground connections are very important to the proper operation of electrical and electronic circuits. Ground
connections are often exposed to moisture, dirt and other corrosive elements. The corrosion (rust) can
become an unwanted resistance. This unwanted resistance can change the way a circuit works.
• Electronically controlled circuits are very sens itive to proper grounding. A loose or corroded ground can
drastically affect an electronically controlled circuit. A poor or corroded ground can easily affect the circuit.
Even when the ground connection looks clean, there c an be a thin film of rust on the surface.
SGI847-A
Revision: March 2010 2008 QX56

PG
BATTERYPG-5
< BASIC INSPECTION >
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BASIC INSPECTION
BATTERY
How to Handle BatteryINFOID:0000000001696239
CAUTION:
• If it becomes necessary to start the engine with
a booster battery and jumper cables, use a 12-volt
booster battery.
• After connecting battery cables, ensure that they are tightly clamped to battery terminals for good
contact.
• Never add distilled water through the hole used to check specific gravity.
METHODS OF PREVENTING OVER-DISCHARGE
The following precautions must be taken to prevent over-discharging a battery.
• The battery surface (particularly its top) should always be kept
clean and dry.
• The terminal connections should be clean and tight.
• At every routine maintenance, check the electrolyte level. This also applies to batteries designated as “low maintenance” and
“maintenance-free”.
• When the vehicle is not going to be used over a long period of time, disconnect the battery cable from the negative terminal. (If
the vehicle has an extended storage switch, turn it off.)
• Check the charge condition of the battery. Periodically check the specific gr avity of the electrolyte. Keep a
close check on charge condition to prevent over-discharge.
CHECKING ELECTROLYTE LEVEL
WARNING:
Never allow battery fluid to come in contact with skin, eyes, fabrics, or painted surfaces. After touch-
ing a battery, never touch or rub your eyes until you have thoroughly washed your hands. If acid con-
tacts eyes, skin or clothing, imme diately flush with water for 15 minutes and seek medical attention.
MEL040F
ELA0349D
MEL042F
Revision: March 2010 2008 QX56