to the right until the engine is cranked. The voltmeter
lead clips must be in good contact with the battery
posts and the starter terminal. Now, turn the voltmeter
selector switch to the No. 4 VOLT position. Before
cranking the engine with the ignition switch ON,
connect a jumper from the secondary terminal of the
coil to ground to prevent the engine from starting
while it is being tested. While cranking the engine,
observe the voltmeter reading which should be within
the manufacturer’s specifications. Unless otherwise
specified by the manufacturer, the voltage loss in each
of the circuits shown in views A, B, and C should not
exceed the value given.
When you test a 6-volt system, the completed
circuit shown in view A allows a 0.2 volt loSS and
that of view B, allows a 0.3 volt loss. When you test
a 12-volt system, the completed circuit shown in
view A allows a 0.4 volt loss and that of view B, a
0.3 volt loss, and that of view C, a 0.1 volt loss. If
testing a 24- or 32-volt system, refer to the
manufacturer’s specifications. If the voltmeter
reading is more than specified for the type of
system being tested, high resistance is indicated in
the cables, switches, or connections. Repeat the
test with the voltmeter connected to each cable,
switch, and connector of the circuit. The maximum
readings taken across these parts should not exceed
the values listed below.
6-Volt System
12-Volt System
Each cable
0.1 volt
0.2 volt
Each switch
0.1 volt
0.1 volt
Each connector
0.0 volt
0.0 volt
STARTER GROUND CIRCUIT
RESISTANCE TEST
Excessive resistance in the ground circuit of the
starting system can cause sluggish cranking action or
failure to crank. It can also seriously interfere with the
operations of the electrical circuits using the same
ground.
To conduct the starter ground circuit resistance test
on a 6-, 12-, or 24-volt series system, perform the
following:
Connect the VOLTMETER leads of the tester, as
shown in figure 4-26, and observe the polarity as you
make the connections. Be sure the voltmeter lead clip at
the battery contacts the battery post and not the battery
cable clamp. Now, turn the voltmeter selector switch to
the No. 4 VOLT position. Before cranking the engine
with the ignition switch ON, connect a jumper lead from
the secondary terminal of the coil to ground to prevent
the engine from starting while it is being tested. While
cranking the engine, observe the voltmeter reading.
Unless otherwise specified by the manufacturer’s
Figure 4-26.-Starter ground circuit resistance test.
4-14
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