On-Vehicle Testing; Starter Motor Will Not Rotate; Starter Motor Solenoid Pull-In Winding Test; Starter Motor Cable And Ground Cable Tests (Voltage Drop) - Jeep J-10 Series 1982 Technical & Service Manual

1F-14 STARTING SYSTEMS
then actuated and begins rotating the engine
crankshaft.
TROUBLESHOOTING
The Service Diagnosis chart may be used to isolate the
source of the problem when the starter motor either
rotates the engine too slowly, will not rotate the engine,
or has abnormal drive engagement.
If the starter motor rotating speed is normal and the
drive pinion gear engages properly with the ring gear
but the engine does not start, a problem exists either in
the fuel system or ignition system.
ON-VEHICLE TESTING
Starter Motor Will Not Rotate
(1) Verify battery and cable condition as outlined in
Chapter ID—Batteries to assure correct voltage is
available.
(2) Inspect and tighten battery and starter motor
cable connections at starter motor solenoid terminals.
(3) Disconnect wire at solenoid S-terminal.
WARNING: Place transmission in Neutral (manual) or
Park (automatic) position and apply parking brake be
fore conducting solenoid test.
(4) Connect jumper wire from battery positive post
to solenoid S-terminal. If starter motor rotates, solenoid
is not defective. Inspect ignition/start switch circuit.
(5) If starter motor does not rotate, connect another
jumper wire from battery negative terminal to solenoid
mounting bracket (manual transmission only) or ground
terminal (automatic transmission only). Ensure good
connection is made. If solenoid energizes, it was not
properly grounded. Remove rust or corrosion and attach
solenoid to inner-fender panel with cadmium-plated
screws (manual transmission only) or test operation of
neutral safety switch (automatic transmission only).
(6) If starter motor does not rotate, remove jumper
wires and connect heavy gauge jumper cable between
battery positive post and starter motor terminal on sole
noid. If starter motor rotates, solenoid is defective and
must be replaced. If starter motor does not rotate, in
spect starter motor.
Starter Motor Solenoid Pull-in Winding Test
This test will determine if the solenoid pull-in winding
is either shorted or open.
(1) Disconnect S-terminal wire from solenoid.
(2) Connect ohmmeter test probes (fig. 1F-13) to S-
terminal and mounting bracket (manual transmission
only) or ground terminal (automatic transmission only).
(3) If solenoid fails test, replace solenoid.
NOTE: A poor solenoid ground can be determined by
connecting one ohmmeter lead to the battery negative
terminal and other lead to S-terminal If resistance is
OPEN
CIRCUIT
OPEN
CIRCUIT
MANUAL TRANSMISSION
OPEN CIRCUIT *-<
OPEN
CIRCUIT
3-5 OHMS
5 OHMS
AUTOMATIC TRANSMISSION 80244
Rg. 1F-13 Ohmmeter Test of Starter Motor Solenoid
greater than in the S-terminal-to-mount bracket test
(fig. 1F-18), the solenoid has a poor ground.
Starter Motor Cable and Ground Cable Tests (Voltage Drop)
The results of voltage drop tests will determine if
there is excessive resistance in the high current circuit.
When performing these tests, it is important that the
voltmeter test lead probes be in contact with the termi
nals that the cables are connected to instead of with the
cables themselves. For example, when testing between
the battery and solenoid, the voltmeter probes must
touch the battery post and the solenoid threaded stud.
Preliminary Preparation for Tests
(1) Remove ignition coil secondary wire from dis
tributor and ground to engine.
(2) Place transmission in Neutral (manual trans
mission) or Park (automatic transmission) and set park
ing brake.
(3) Ensure battery is fully charged.
Test Procedure
Follow the steps as outlined in the Starter Motor
Voltage Drop Tests DARS charts.
Full Load Current Test
(1) Prior to performing full load current test, bat
tery must be fully charged as described in Chapter
ID—Batteries.
NOTE: The lower the available voltage, the higher the
current flow.