Starting System Circuits; Fusible Link; Moveable Pole Shoe Operation - Jeep J-10 Series 1982 Technical & Service Manual

1F-12 STARTING SYSTEMS
PIVOT
DRIVE YOKE
RETURN
SPRING
PINION
GEAR
CLUTCH
MOVEABLE
POLE SHOE
FIELD WINDING
(CONTAINS
HOLD-IN COIL
WINDING)
ARMATURE
FIXED POLE SHOE
70108
Fig. 1F-11 Moveable Pole Shoe Operation
The ground circuit for the solenoid pull-in winding is
completed through the solenoid mounting bracket on
manual transmission equipped vehicles.
On vehicles equipped with an automatic transmission,
the pull-in winding is grounded through an additional
terminal on the bottom of the solenoid. A wire connected
to this terminal provides a ground path from the neutral
safety switch located on the transmission. The pull-in
winding ground circuit is completed at the neutral
safety switch only when the automatic transmission
gear selector is placed in Neutral or Park.
NOTE: The neutral safety switch and back-up lamp
switch are enclosed in a single housing.
The starter motor solenoid pull-in winding is ener
gized when battery voltage is applied to the S-terminal
of the solenoid and the pull-in winding is grounded.
When the solenoid pull-in winding is energized, the con
tact disc is forced into the closed position. The disc
mates with two contacts in the solenoid and this com
pletes the circuit between the battery and the starter
motor.
All starter motor solenoids have an I-terminal that is
connected to the ignition system. When the starter mo
tor is in operation, the I-terminal provides full battery
voltage for the ignition coil. This circuit bypasses the
resistance wire that provides voltage for the coil after
the engine starts. Refer to Chapter 1G—Ignition Sys
tems for additional information.
CAUTION: Starter motor solenoids used in previous
years (before solid-state ignitions) look similar to the
solenoids presently used but are very different inter
nally. Use of the wrong type solenoid can damage the
neutral safety switch. Verify the part number stamped
on the replacement solenoid before installation.
CAUTION: Starter motor solenoids are equipped with
both blade terminals and long studs. The blade termi
nals are attached to the long studs and held in place by
retaining nuts. Loosening of the retaining nuts could
cause the loss of iiiternal connections and necessitate
replacement of the solenoid.
Neutral Safety Switch
The Neutral Safety Switch is a three-terminal plunger
switch mounted on the automatic transmission case.
The two outer terminals connect to the back-up lamp
circuit, while the center terminal provides a ground path
for the starter motor solenoid circuit. Ground is pro
vided only when the automatic transmission is in Park
or Neutral position.
Starting System Circuits
The starting system has two electrical circuits, a low
current circuit and a high current circuit (fig. 1F-12).
The low current circuit is the control circuit. It includes
the connections and wires leading from the ignition
switch to the S-terminal on the starter motor solenoid,
and from the ground terminal of the starter motor sole
noid to the neutral safety switch on automatic transmis
sion equipped vehicles. The high current circuit runs
from the battery through the starter motor solenoid to
the starter motor to ground. This circuit uses heavy
gauge cables because of the large current flow required
for the starter motor.
Fusible Link
A fusible link is used in the low current starting
system circuit (fig. 1F-12). Current flows from the
starter motor solenoid battery terminal by cable to the
battery positive terminal. From the solenoid battery
terminal, voltage is also distributed to other vehicle
circuits. A 14-gauge fusible link is connected between
the solenoid terminal and the main body wire harness.
This fusible link protects the complete vehicle electrical
system as well as the solenoid.
Fusible links are covered with a special non-flam
mable insulation. Each link is manufactured with a spe
cific load rating and is intended for a specific circuit.
Replacement links are available from Jeep service parts
sources.
OPERATION
The starter motor low current circuit is controlled by
the ignition/start switch (fig. 1F-12). The ignition/start
switch applies battery voltage to the starter motor sole
noid S-terminal when the ignition key is in the Start
position. This energizes the solenoid pull-in winding,
which completes the high current circuit between the
battery and the starter motor. The starter motor is