Basic Diagnostic Testing
Starter Motor Testing
[
1
I
Starter
-
Current
The Bettery tests and the Voltage Drop tests have verified that there
is adequate battery voltage at the starter. Next, check for excessive
starter motor current draw.
Connect a Current Clamp around
the negative
(-1
or positive
(
+
)
battery cable.
Set the rotary switch to the
400
mV setting.
Note: 1mV
=
IAmp.
Set the MinIMax feature on the
meter. The Min reading will be
the negative current draw.
Disable the ignition so the en-
Black
(-)
gine doesn't start; crank the
engine for 2-3 seconds.
Note:
The current clamp measures amps in
the direction of electrical flow. Make
sure the arrow on the clamp is pointed
in the
djrection of the current flow in
the cable.
Quick
Test,
Turn the ignition and all accessories
OFF.
Place the clamp on the battery
cable, then turn the headlights on.
If
the reading is not negative, discon-
nect the clamp, turn it over and
reconnect.
Approximate Amperage Draw
Basic Diagnostic Testing
Charging System Tests
[I
]
Battery
(
+
)
This test checks for alternator
output voltage at the
batterv.
Set the rotary switch to Voltage
Connect the positive
(
+
)
lead to
the
positvie
(
+)
battery termi-
nal.
Connect the negative
(-)
lead to
the negative
(-1
battery termi-
nal.
Set the MinlMax feature on the
meter.
Make sure all vehicle accesso-
ries are turned
OFF.
Start the engine and hold at
1500 RPM.
A
reading of 13.1-1 5.5 volts is an
acceptable charging rate. If the
voltage is low check for:
Loose, cracked, or glazed drive
belt
Loose or faulty wires or connec-
tors
Defective alternator or regula-
tor. See
[21
Alternator Voltage
Output
(
+
1,
Loaded.
4
Cyl.
6-8
Cyl., under 300 CID
6-8
Cyl., over 300 CID
150-1 80 Amp. Maximum
180-21
0
Amp. Maximum
250 Amp. Maximum
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