voltage; open is further down the circuit than the relay.
no voltage; open is between SW1 and relay (point B).
5) 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
above example.
TESTING FOR“SHORTS”IN THE CIRCUITNLGI0005S0303To simplify the discussion of shorts in the system please refer to
the schematic below.
SGI847
Resistance Check Method
1) Disconnect the battery negative cable and remove the blown
fuse.
2) Disconnect all loads (SW1 open, relay disconnected and sole-
noid disconnected) powered through the fuse.
3) Connect one probe of the ohmmeter to the load side of the fuse
terminal. Connect the other probe to a known good ground.
4) 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.
5) 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.
6) 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
1) Remove the blown fuse and disconnect all loads (i.e. SW1
open, relay disconnected and solenoid disconnected) powered
through the fuse.
2) Turn the ignition key to the ON or START position. Verify bat-
tery voltage at the B + side of the fuse terminal (one lead on
the B + terminal side of the fuse block and one lead on a known
good ground).
3) 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.
4) 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).
HOW TO PERFORM EFFICIENT DIAGNOSES FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont’d)
GI-26
How to Handle BatteryNLSC0003CAUTION:
If it becomes necessary to start the engine with a booster
battery and jumper cables,
1) Use a 12-volt booster battery.
2) After connecting battery cables, ensure that they are
tightly clamped to battery terminals for good contact.
3) Never add distilled water through the hole used to check
specific gravity.
MEL040F
METHODS OF PREVENTING OVER-DISCHARGENLSC0003S01The following precautions must be taken to prevent over-discharg-
ing 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”.
MEL041F
+When the vehicle is not going to be used over a long period of
time, disconnect the negative battery terminal.
MEL042F
+Check the charge condition of the battery.
Periodically check the specific gravity of the electrolyte. Keep
a close check on charge condition to prevent over-discharge.
CHECKING ELECTROLYTE LEVELNLSC0003S02WARNING:
Do not allow battery fluid to come in contact with skin, eyes,
fabrics, or painted surfaces. After touching a battery, do not
touch or rub your eyes until you have thoroughly washed your
hands. If acid contacts eyes, skin or clothing, immediately
flush with water for 15 minutes and seek medical attention.
BATTERY
How to Handle Battery
SC-3
