GI-32
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
Revision: 2006 January2006 M35/M45
VOLTAGE CHECK METHOD
To help in understanding the diagnosis of open circuits please refer to the previous schematic.
In any powered circuit, an open can be found by methodically checking the system for the presence of voltage.
This is done by switching the DMM to the voltage function.
Connect one probe of the DMM to a known good ground.
Begin probing at one end of the circuit and work your way to the other end.
With SW1 open, probe at SW1 to check for voltage.
voltage; open is further down the circuit than SW1.
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
terminal (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).
SGI847-A
SC-4
BATTERY
Revision: 2006 January2006 M35/M45
BATTERY PFP:00011
How to Handle Battery NKS003NF
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 gravity of the electrolyte. Keep a
close check on charge condition to prevent over-discharge.
MEL040F
ELA0349D
MEL042F
