1953 JEEP DJ ignition

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL

H

12746

FIG.
H-l8—VACUUM
ADVANCE
MECHANISM
(DELCO)

A—Full
Advance

B—No
Advance
1—Vacuum
Pull
Rod
e.
To adjust breaker point cam dwell and set tim­
ing of engine, refer to
Pars.
C-10 and
C-ll.
H-31. Coil
— V-6 Engine

The
sealed coil
does
not require any special service
other than keeping the terminals and wire connec­
tions clean and tight.

The
positive (+) terminal of the coil is connected
to the ignition switch through the ballast resistor,
and
is also connected directly to the starter
sole­

noid to by-pass the resistance during cranking of
engine.
The
negative (—) terminal is connected to the

distributor.
The secondary (high tension) terminal
is connected by a short cable to the center terminal
in
the distributor cap.

Always
make certain the coil wires are connected to the proper coil terminals to ensure correct
coil
polarity.

Note:
The ignition coil and ballast resistor must
be of the same manufacturer. Ballast resistors
and
ignition coils of one manufacturer are inter­changeable with both units of the other. H-32.
Ballast
Resistor

•
V-6 Engine.

An
ignition ballast resistor is in series with the
primary
winding of the coil. The ballast resistor
helps regulate the flow of
primary
current through­
out the speed range. At low
speeds
when the con­
tacts remain closed longer, the ballast heats and
increases in resistance, thereby limiting the flow of

primary
current. At higher
speeds
when the con­
tacts remain closed for shorter periods of time, the ballast
cools
and thereby decreases in resistance
to allow more
primary
current and reduce the
fall

off
in
available voltage.
During
starting, the resistor compensates for the lowered battery
voltage
re­
sulting from the starter load and permits an in­ crease in
primary
current, resulting in a higher
secondary
voltage
for starting.
The
only
test
required of the ignition ballast re­
sistor is a continuity check. Characteristics of the ballast produce wide variations in resistance with
changes in ballast temperature. Therefore, check­ ing
voltage
drop across the ballast would be mis­
leading.

Caution:
Never make a connection that connects
the ballast across the battery as this
will
burn
the ballast resistor winding.

H-33.
Spark
Plugs

Clean
and gap
spark
plugs as described in
Par.
C-4.
Inspect them for excessive burning and erosion of
electrodes, blistering of porcelain at the firing tip,

black
deposits, or fouling. These conditions indicate
that the plugs have not been operating at the cor­

rect
temperature.

Note:
Prolonged idling just before removing and
checking the plugs should be avoided as it may
produce false indications.

Spark
plug operating temperatures may have been
too hot, too cold, or normal as described.

a.
At too hot a temperature, the tip of the insulator
will
show
dark
spots
and blisters after fairly short service. As high-temperature operation is con­
tinued, the whole insulator
nose
will
discolor, show­
ing fused and blistered
deposits
near the electrode
as well as considerable erosion and burning of the
electrodes. After extreme service, the porcelain it­ self may be fused, cracked, and blistered at the tip.

The
electrodes
will
show extreme erosion and
burn­

ing and possibly even surface cracking.

Note:
If such cracking appears on certain plugs
after fairly short service, it may be caused by water
leaks in the associated cylinders.
b. At too cold a temperature plug operation, in
the early
stages,
will
result in a
dull
black
sooting

of the plug.
This
condition frequently is found in new vehicles during the break-in period and is no
indication of trouble in this case. As the condition progresses, black
deposits
of oil and carbon build
up on the base of the shell and on the insulator

until,
in extreme cases, the space
between
insulator

and
shell may be almost completely filled. Excessive
electrode erosion
will
seldom be found in cases of cold plug operation. These indications can be pro­
duced by the use of an excessively
rich
air-fuel mixture and the carburetor should be checked if
this condition is suspected. Fouling
will
also be
caused by leaking rings or intake valve
guides
that
permit excessive oil to reach the combustion
chambers.
The use of a hotter plug
will
help
burn

away
some
of this fouling but the mechanical con­ dition of the
engine
should be corrected.
c. In normal temperature operation the plug
will
accumulate grayish-tan to reddish-brown
deposits

with
fairly uniform discoloration of the insulator
nose
and slight, localized electrode erosion. If the
insulator shows any blotches, blisters,
irregular
dis­
coloration, etc., look for hot-plug symptoms. Too
hot or too cold plug operation may be caused by
the use of plugs of other than the specified heat

rating
but if the plugs are as specified a hotter or 187

H

ELECTRICAL
SYSTEM
Regulator
ground screw to battery ground post
—.03-volt maximum.

Generator
frame to battery ground post—.03-volt
maximum.

H-47.
Test Procedure

a.
Circuit
Breaker—Connect
an ammeter in series between the regulator B-terminal and the lead
wire
removed from that terminal. Connect a
voltmeter between the regulator
A-terminal
and the regulator mounting base. Disconnect the field lead

from
the regulator
F-terminal
and insert a variable resistance (3 amp., 50 ohm capacity) between the

lead
and the regulator terminal. Run the generator
at about 1000 generator rpm. Insert all the re­
sistance in the field
circuit,
then slowly reduce the
resistance noting the voltage reading just before the change caused by the closing of the circuit

breaker.
Increase the charging rate to the figure
specified for the regulator being tested then reduce
the charging rate by inserting resistance in the
field
circuit.
Note
the voltmeter and ammeter

reading
just before the circuit breaker
opens
and
the ammeter reading drops to zero. The closing voltage and the opening voltage or current should
be within the limits specified. An accurate method
for noting the exact instant of the opening or closing
of the circuit breaker is to connect a headphone (2000 ohms or higher) to the battery and armature

terminals
of the regulator. When the contacts
open or close a
click
will
be
heard
in the headphones.
To
adjust the closing voltage change the armature

spring
tension by bending the hanger at the lower end of the spring. Increase the spring tension to

raise
the closing voltage or decrease the tension
to lower the closing voltage. To adjust the opening voltage raise or lower the stationary contact
keeping the contacts perfectly aligned. Increasing
the contact gap lowers the opening
'
voltage.
Change
the contact gap by expanding or contract­
ing the stationary contact bracket, keeping the
contacts aligned. Do not adjust the gap between
the contacts to less than the specified minimum.

b.
Voltage Regulator—Connect the ammeter as in

step
a. Connect the voltmeter between the regulator
B-terminal
and the regulator base. Remove the

variable
resistance from the field
circuit.
Run the
generator at
half
output for 15 minutes to bring
the regulator to normal operating temperature.

Keep
the cover on the regulator during the
warm-

up period and also when taking readings.
Stop the engine then bring it up to approximately 2500 generator rpm. Adjust the amperage to
half

maximum
output by turning on lights or accessor­
ies and then
note
the voltmeter reading.
This
read­

ing should be within the limits specified for the voltage regulator operation. To adjust the oper­
ating voltage change the
armature
spring tension by
bending the hanger at the lower end of the
arma­

ture
spring. After each adjustment
stop
the engine then restart it.
Bring
it up to speed and adjust the

current
before taking a reading. In order to obtain

an
accurate indication of the operation of the volt­
age regulator unit connect a headphone (2000 ohm

or
higher) between the
F-terminal
and ground to

pick
up the sound of the opening and closing of the
contacts. The clicks should be regular and clear without irregularities or missing. If the
tone
is not

clear
and regular remove the regulator cover and
inspect the contacts. The contacts should be flat
and
not burned excessively and should be aligned
to make
full
face contact. If the contacts need
cleaning refer to paragraph d for the method.

c.
Current
Regulator—Connect the regulator and the
test
equipment as in
step
b. Running the generator at approximately 3000 generator rpm.,

turn
on lights and accessories so that the generator must charge at maximum rate. The ammeter should give a reading within the limits specified.

To
adjust opening amperage, change the armature

spring
tension by bending the hanger at the lower
end of the armature spring. After each adjustment,

stop
the engine, then restart it.
Bring
the engine up to speed and take an ammeter reading. Keep
the cover on the regulator when taking
these

readings.

Connect
a headphone (2000 ohms or higher) be­
tween the regulator
F-terminal
and ground to pick
up the sound of opening and closing of the contacts.

Clear,
regular clicks should be heard over the
headphones; they should not be
irregular
or missing.
If
the
tone
is not clear and regular remove the
regulator cover and inspect the contacts. The
contacts should be flat and not burned excessively

and
should be aligned to make
full
face contact. If
the contacts need cleaning refer to paragraph d.
below for the method.

d.
Contacts—Inspect the contacts on all three
units.
In normal use the contacts
will
become

grayed.
If the contacts are burned or dirty or if they are not smooth, file the contacts with a #6

American,
Swiss cut, equalling file. Move the file

parallel
and lengthwise to the armature.
File
just
enough so that the contacts present a smooth
sur­

face toward each other. It is not necessary to remove every trace of pitting. After filing, dampen

a
piece of linen or lintless bond tape in refined

carbon
tetrachloride and draw the tape between
the contacts. Repeat with a dry piece of tape. Use
clean
tape for each set of contacts.
e. Recheck—Operate the unit at
half
maximum
output for five minutes with the cover on the regu­

lator.
Repeat the testing procedure for all units as described in a, b, c above. Be sure cover is on regu­

lator
when taking readings.

H-48.
Quick
Checks

H-49.
Low Charging Rate with a
Fully
Charged
Battery

A
fully charged battery and a low charging rate
indicates normal regulator operation.
A
further check of the regulator operation can be
made by using the starting motor for 5 to 10
seconds with the ignition switch in the "off" posi­ tion.
Then
start the engine and operate at a genera­
tor speed of 2500 to 3000 rpm. The charging rate should rise to its maximum value then taper off to

a
minimum charge as the battery becomes charged.

H-50.
High Charging Rate with a
Fully
Charged
Battery

This
is usually an indication that the voltage regu­

lator
is not operating correctly. The high voltage 192

'Jeep1
UNIVERSAL
SERIES SERVICE
MANUAL

H
will
cause the battery to gas excessively and
will

shorten the life of the ignition contacts and, in

general,
will
have a detrimental
effect
on all con­
nected load.

Connect
an ammeter in series with the regulator
"B"
terminal and the lead removed from the termi­

nal.
Run the generator at a medium speed and per­

form
the following operation. After each
test
is
completed reconnect whatever leads have been opened.

H-51.
Test One
Disconnect the field lead at the generator.

a.
Output drops to zero—shorted field circuit in regulator or in wiring harness. See
test
2.

b.
Output
does
not drop—shorted field circuit in
generator. Inspect generator.

H-52.
Test Two
Disconnect the field lead at the regulator.

a.
Output drops to zero—shorted field in regulator.
See
test
3.

b.
Output
does
not drop—shorted wiring harness.

Repair
or replace wiring harness.

H-53.
Test
Three

Remove the regulator cover and hold the
voltage

regulator contacts open.

a.
Output drops to zero—regulator contacts stick­

ing,
regulator out of adjustment, or regulator in­ operative.
Check
operation
(test
5), check for high
resistance
(test
4), and clean contacts per instruc­
tions in Par. H-56.

b.
Output
does
not drop—shorted field circuit in
the regulator.
Clean
the regulator contacts and in­ spect the regulator visually for incorrect wiring be­
tween units and shorted leads.

H-54.
Test
Four

Operate
the units at 10 amperes output and meas­

ure
the
voltage
drop from the regulator base to
the generator frame.

a.
Voltage reading below .03 volts—ground
cir­
cuit
is satisfactory. See
test
5.

b.
Voltage reading above .03 volts—Inspect ground

circuit
for poor connections and eliminate the high
resistance. See
test
5.

H-56.
Test
Five

Connect
a headphone from the regulator field ter­
minal
to the base and hold the current regulator
contacts closed.

a.
A steady beat is heard—voltage regulator oper­
ating.
Reset regulator as in the operation
test,

Par.
H-47.

b.
An unsteady beat is heard—dirty or sticking
contacts.
Clean
contacts per instructions in Par.

H-56.
c.
No beat is heard—inoperative
voltage
regulator
unit.
Adjust regulator operation as in the operation

test.
If the regulator cannot be adjusted within
limits,
remove for overhaul.
H-56.
Cleaning of Contacts

Clean
the
voltage
regulator contacts with a #6

American
Swiss cut equalling file.
File
lengthwise

and
parallel to the armature and then clean the
contacts with clean linen tape.
First
draw a piece
of tape that has been wet with carbon tetrachlor­
ide
between
the contacts then follow with dry tape. Reset the regulator operation as in the oper­
ation
test,
Par. H-47.

H-57.
Low Battery and a Low or No Charging Rate

Check
all wiring for
loose
connections, frayed in­
sulation and high resistance connections and cor­
rect
any fault.

Make
sure the generator operates correctly with­
out the regulator in the
circuit.
Remove the "A"

and
"B" leads from the regulator and connect an
ammeter
between
them. Remove the field lead from
the regulator and while operating at idle speed
touch the field lead to the regulator base. Increase
the speed slowly noting the charging rate. Do not

increase
the output above the rated output of the generator. If the generator output
will
not build

up,
inspect the wiring harness for shorts and
opens

and
remove the generator for an overhaul.

Connect
an ammeter
between
the battery lead and
the regulator
"B"
terminal. Connect the field lead to the regulator "F" terminal and connect the

armature
lead to the regulator
"A"
terminal.
Con­

nect a voltmeter from the regulator
"A"
terminal to
the regulator base. Operate the generator at a medium speed and perform the following
tests:

H-58.
Test Six

Read
the voltmeter.

a.
Voltage builds up—open series
circuit.
See
test
7.
b.
Voltage
does
not build up—regulator out of ad­
justment, field circuit open, grounded series
circuit.
See
test
8.

H-59.
Test Seven
Remove the regulator cover and with the generator
operating at a medium speed hold the circuit

breaker
contacts closed.

a.
Ammeter shows no charge—open
circuit
breaker
shunt winding, incorrect setting of circuit breaker,

or
dirty contacts.
Clean
contacts and reset circuit

breaker
as in
Par.
H-47d. If the circuit breaker
can­
not be set, the shunt coil is open and the regulator
should be removed for overhaul.

b.
No generator output—clean the circuit breaker
contacts and try the
test
again. If there is
still
no
charge the series windings are open and the regu­

lator
should be removed for overhaul.

H-60.
Test
Eight

Run
the generator at idle speed and momentarily
connect a jumper from the
F-terminal
to the regu­

lator
base.

a.
Voltage builds up—open field circuit or regula­
tor out of adjustment. See
test
9.
b.
Voltage
does
not build up—grounded series
cir­

cuit.
Remove regulator for overhaul. 193

H

ELECTRICAL
SYSTEM H-61.
Test Nine

Operate
at a medium speed with the jumper re­ moved. Remove the regulator cover and hold the

voltage
regulator contacts closed.

a.
Voltage builds up—voltage regulator contacts
burned
or dirty or incorrect regulator setting.

Clean
the contacts and adjust the regulator as in

Par.
H-47d.

b.
Voltage
does
not build up—clean contacts and
repeat
test.
If the
voltage
still
does
not build up, see
test
10.

H-62.
Test Ten
Remove the regulator cover and hold the current
regulator contacts closed.

a.
Voltage builds up—current regulator contacts
burned
or dirty or incorrect regulator setting.

Clean
the contacts and adjust the regulator as in

Par.
H-47d.

b.
Voltage
does
not build up—clean the contacts

and
repeat the
test.
If the
voltage
still
does
not

build
up remove the regulator for an overhaul.

H-63. ALTERNATOR CHARGING SYSTEM

Most vehicles have, as standard equipment, a 35-

amp.,
12-volt, negative ground alternator and a
transistorized
voltage
regulator.
The
alternator charging circuit consists of the
battery, alternator,
voltage
regulator, ignition
switch,
and charge indicator light.

An
alternator differs from a conventional DC
shunt generator in that the armature is stationary,

and
is called the stator, while the field rotates,
and
is called the rotor.
With
the alternator con­
struction,
the higher current values involved in
the stator may be conducted to the external circuit through fixed leads and connections, rather than
through a rotating commutator and brushes, as in the DC generator.

The
alternator employs a three-phase stator
winding. The rotor consists of a field coil encased
between
six poled interleaved sections, producing

a
twelve
pole
magnetic field with alternator north

and
south poles. By rotating the rotor inside the stator, an alternating current is induced in the stator windings.
This
alternating current is
changed to direct current by
diodes
and conducted
to the output terminal of the alternator.
Six
silicon
diode
rectifiers act as electrical one-way valves.
Three
of the
diodes
have negative polarity

and
are grounded. The other three
diodes
have
positive polarity and connected to the output
terminal.
In all alternators discussed in this

manual,
the
diodes
are pressed into heat sinks.

There
are two heat sinks, one positive and the
other negative.

Since
the
diodes
have a high resistance to the
flow of
current
in one direction and a low resistance
in
the
opposite
direction, they are connected in a
manner
which allows current to flow from the
alternator to the battery in the low resistance
direction.
The high resistance in the
opposite

direction prevents the flow of current from the
battery to the alternator. Because of this feature,
no
circuit
breaker
is
required
between
the alternator
and
the battery.
Residual
magnetism in the rotor field
poles
is
negligible. Therefore the starting field current must be supplied by the battery. It is connected
to the field winding through the ignition switch

and
charge indicator lamp.
As
in the DC shunt generator, the alternator
voltage
is regulated by varying the field current.
In
these
alternator systems, this is accomplished
electronically in the transistorized
voltage
reg­
ulator.
No current regulator is required since all
alternators have self-limiting current character­
istics.

The
entire DC output of the alternator has to pass
through the isolation diode. The isolation
diode
is
not essential for rectification. Its purpose is threefold.
It
provides automatic solid
state
switch for
illumi­

nating the alternator charge
-
discharge indicator
light when the alternator is not charging properly.
It
automatically connects the
voltage
regulator to
the alternator and battery when the alternator is
operating.
It
eliminates electrical leakage across the alternator

diodes
so that leakage is negligible when the vehicle
is not in use.
The
isolation
diode
is mounted in a separate alumi­

num
heat sink. The 35-amp. alternator has a single
silicon diode. The alternator is designed to supply the electrical demands of the battery and the
accessory circuits through a wide range of
engine

speeds. The alternator is lighter and more compact

than
a conventional DC shunt generator of com­

parable
electrical size.

The
principal
components of the alternator are
the stator, the rotor, the slip ring end head, the

drive
end head, the
diode
rectifiers, and the isolation diode.

a.
The stator consists of a laminated iron core on

which
the three-phase windings are wound in
slots
around
the inside circumference. A
pair
of leads
are
connected to each of the three points of the
winding. One of each
pair
of leads connects to a
negative
diode
rectifier and one to a positive
diode
rectifier.

b.
The rotor consists of a single field coil encased

between
two six-fingered, interleaved iron sections assembled to the shaft. The two ends of the field
coil
are connected to two slip rings which are in­
sulated from each other and from the shaft.
c. The slip ring end head supports the rectifier heat sinks; a prelubricated sealed
ball
bearing, in

which
the rotor shaft rotates; and the brush holders
and
brushes.

d.
The drive end head supports a prelubricated
sealed
ball
bearing in which the drive end of the rotor shaft rotates.
e. The
diode
rectifiers are pressed in the rectifier brackets or heat sinks and are connected to the
stator leads.
f. The isolation
diode
is pressed in the aluminum heat sink mounted to the
rear
of the alternator. The
complete assembly is covered with a red insulating coating.

For
repairing the alternator, many of its major components are furnished as complete assemblies

including:
complete brush assembly which requires 194

'Jeep*
UNIVERSAL
SERIES SERVICE
MANUAL

H
no soldering or unsoldering of leads; two complete

rectifying
diode assemblies
which
eliminate the need
for removing and replacing individual diodes; a
corpplete isolation diode assembly; and a rotor
assembly complete with shaft,
pole
pieces, field

coil,
and slip rings.

The
transistorized
voltage
regulator is an electronic
switching device. It
senses
the
voltage
appearing
at the auxiliary terminal of the alternator and
supplies the necessary field current for maintaining
the system
voltage
at the output terminal. The
output current is determined by the battery electri­
cal
load; such as headlights, heater, etc.

The
transistorized
voltage
regulator is a sealed

unit,
has no adjustments, and must be replaced
as a complete unit.

H-64. ALTERNATOR
PRECAUTIONS

The
following precautions must be observed to
prevent damage to the alternator and regulator.

a.
Never reverse battery connections. Always

check
the battery polarity with a voltmeter before

any
connections are made to be sure that all con­
nections correspond to the battery ground polarity of the vehicle.

b.
Booster batteries for starting must be properly
connected. Make sure that the negative cable of
the booster battery is connected to the negative

terminal
of the battery in the vehicle. The positive
cable of the booster battery should be connected
to the positive terminal of the battery in the
vehicle.

c.
Disconnect the battery cables before using a fast charger.

d.
Never use a fast charger as a booster for

starting
the vehicle.

e.
Never disconnect the
voltage
regulator while
the
engine
is running.

f.
Do not ground the alternator output terminal.
g.
Do not operate the alternator on an open
circuit
with
the field energized.

h.
Do not attempt to polarize an alternator.

These
precautions are stated here as an aid to

service
personnel. They are also restated at appro­

priate
places in the
text
of this section of the
manual.

H-65. ALTERNATOR
CHARGING
SYSTEM SERVICE
Important:
All alternator
tests
for the 35, 40 and
55 amp alternator are the same, however, there is a
difference
between
the location of the various ter­

minals
and field current specifications. The field

current
of the 35 amp alternator should be 1.7 to 2.3 amps, 40 and 55 amp alternators should be 1.8
to 2.4 amps, with
full
battery
voltage
applied to
the filed coil. Disassembly and assembly procedures

are
the same for all three alternators.
Terminal
locations and wire harness color
codes
for the 35,
40 and 55 amp alternator are shown in Fig. H-38.

H-66.
Service Diagnosis

In
diagnosing a suspected malfunction of the

alternator
charging system, consideration must
be given to the complete electrical power plant of the vehicle; including the alternator, regulator,
ignition switch, charge indicator lamp, battery,

and
all associated wiring. If it is suspected that the

alternator
is not fully charging the battery and

fulfilling
the electrical requirements of the electrical
system, several checks should be made before

checking
the alternator itself:

Note:
Whenever service is required in connection

with
an alternator problem, the first
step
should be to verify that the wiring harness hook-up is correct
as indicated in Fig. H-38.

a.
Test the condition of the battery and
state
of
charge
(Par. H-2).
If the battery is not fully charged
and
in
good
condition, use a replacement battery
for making alternator system
tests.

Caution:
Make certain that the negative battery

post
is connected to ground when making the
battery installation. Serious damage to the alter­

nator
can result if battery polarity is reversed.

b.
Check
fan belt for proper tension (Par.
C-27).

Caution:
To increase belt tension, apply pressure
to alternator front housing only as permanent damage can result if pressure is applied to
rear

housing.

H-67.
Alternator In Vehicle Tests

The
following
tests
are made with the alternator

in
the vehicle with output and regulator connec­
tions maintained to the alternator except as noted

in
Fig. H-27 and H-28. The field plug and
voltage
regulator are disconnected for
these
tests.
The

tests
are given in proper order and detail in the
following paragraphs.

a.
Isolation Diode Test: To determine if the isola­
tion diode is open or shorted, refer to Par. H-69.

b.
Alternator Output Test: To isolate the trouble
to the alternator or regulator, refer to Par. H-70.

c.
Alternator
Field
Circuit
Test: To determine the condition of the field
circuit
(brushes and rotor),

refer
to Par. H-73.

d.
Brush
Insulation
and Continuity
Test:
To deter­
mine the condition of the
brush,
refer to
Par.
H-75.

e.
Rotor In-Vehicle Test: To determine whether
the rotor coil is open or shorted, refer to
Par.
H-73.
f. Any further
tests
must be conducted with the

alternator
removed and disassembled. When this
is done, the condition of the rotor, the rectifying

and
isolation diodes, and the stator can be further
tested.

A
commercial alternator tester Sun
Electric
Model

VAT-20
or equivalent can be used to make all
necessary
tests
on the alternator system. If a com­

mercial
tester is used, follow the recommended
testing procedure outlined by the tester manu­

facturer.
If
a commercial tester is not available, follow the
testing procedure as outlined in this manual.

H-68.
Test Equipment

a.
Volt Ampere Tester such as Sun
Electric
Model

VAT-20
or equivalent with meter ranges as shown

in
the following list can be used. 195

H

ELECTRICAL
SYSTEM DC
ammeter — 0 to 60 ampere

DC
ammeter — 0 to 5 ampere

DC
voltmeter — 0 to 16 volt
Rheostat — 40 ohm capable of
handling
3 amps.

Carbon
Pile — 45 amperes

b.
Diode Rectifier Tester C-3829.

c.
12-volt DC
test
lamp.

d.
Ohmmeter of any commercial type is not ab­solutely necessary but can be helpful.

H-69.
Isolation Diode
Check

With
the ignition key in the off position the correct voltage at the auxiliary terminal is zero volts. If
voltage measured at auxiliary terminal is the same as voltage at output terminal, the isolation diode
is shorted. In most cases, the charge indicator lamp
would be glowing with the ignition off if the isola­ tion diode were shorted. Refer to Fig. H-23.
GREEN

DC
VOLTS
13401

FIG.
H-23—ISOLATION DIODE
TEST-
SHORTED DIODE
With
the engine running the correct voltage at the

auxiliary
terminal is 15.4 volts and at output ter­

minal
is 14.4 volts. If voltage of auxiliary terminal
is 15.4 volts, while at output terminal it is 12 volts

or
battery voltage, the isolation diode is open. In
most cases, this would be indicated by the charge

GREEN

TO
CHARGE
INDICATOR
LAMP1

15.4
VOLTS BLACK
VOLT

REG DC
VOLTS

BATTERY

DC
VOLTS
FIG.
H-24—ISOLATION DIODE
TEST-

OPEN DIODE
indicator
lamp glowing when the engine is running.

Refer
to Fig. H-24.

If
the isolation diode is shorted or open, the heat

sink
and diode should be replaced as an assembly.

At
the time of manufacture, the diode is pressed into the heat sink and the complete assembly is in­
sulated from the alternator housing.

H-70.
Alternator Output Test

This
test
excludes the regulator from the alternator
system, thereby isolating the problem to either the regulator or alternator. Disconnect field and voltage regulator plug and
connect jumper from auxiliary terminal to field

terminal.
Start
engine and run at idle. Refer to

Fig.
H-25.
DC
VOLTS

13403

FIG.
H-25—ALTERNATOR OUTPUT
TEST
If
voltage at auxiliary terminal rises to 15 or 16
volts now, when it did not with voltage regulator
connected, then defect is in regulator and it should
be replaced. If voltage
does
not rise at auxiliary

terminal,
defect is in alternator stator or rectifier diodes, if field circuit checked out properly. For
defects
in stator or diodes, remove alternator from vehicle.

If
rated current output is obtained with at least 13
volts but less than 15 volts at the output terminal,
the alternator is functioning properly.

Caution:
Do not exceed rated current output of
alternator
by increasing load on alternator.

If
rated
current
output cannot be obtained, proceed

with
the
tests
and checks given in the following
paragraphs
and isolate the cause.
Note: The system is designed to produce slightly
more output at low operating temperatures and less
at higher temperatures to accommodate the
varying
demands of electrical power normally consumed at

these
temperatures.

H-71.
Regulator Test

The
regulator should be checked with an alternator
that is functioning properly. If the alternator is questionable, perform the Alternator Output Test
(Par
H-70) which excludes the regulator from the

charging
system and, therefore,
tests
the condition
of the alternator alone. 196

'Jeep'
UNIVERSAL SERIES SERVICE
MANUAL

H
H-72.
Removal
and
Installation
of

Voltage Regulator

The
transistorized
voltage
regulator is a sealed unit.
It
cannot be disassembled or adjusted. If found to
be defective in any way, it must be replaced as
a
unit.

The
transistorized
voltage
regulator is mounted on
the fender dust shield by three mounting screws.

Wiring
connections to the charging circuit are made through a three-prong connector.

To
remove the regulator, disconnect the three
-
prong connector and remove the three mounting

screws.
Installation of the regulator is the reverse
of the removal. (Refer to Fig. H-26.)
FIG.
H-26—VOLTAGE
REGULATOR

H-73.
Alternator Field Circuit Test

Voltage
Test — Refer to Fig. H-27.

a.
With the ignition key on and
engine
not
run­
ning,
the correct
voltage
at the auxiliary terminal is
approximately 1.5 volts. If the
voltage
at auxiliary

terminal
is higher than 2 volts, field circuit is defective — check brushes.
GREEN

13404

FIG.
H-27—FIELD
CIRCUIT TEST—VOLTAGE If
voltage
reads zero volts at auxiliary terminal,
check charge indicator lamp and associated circuit.
If
this
voltage
is not correct, continue with the fol­
lowing
test
described in paragraph b.
Amperage Test — Refer to Fig. H-28. b.
This
test
evaluates complete field circuit, inde­
pendent of
voltage
regulator.
Circuit
is through
brushes, slip rings, rotor to ground. With ignition switch off, current should be 2 to 2.5 amps. If
less

than
this, check brushes and slip rings. It is de­

sirable
to use a field rheostat in series with meter
for protection of the meter. If field is shorted, ex­
cessive current
will
flow through meter and dam­
age may result.
GREEN
FIELD
WIRE

DISCONNECTED

13405

FIG.
H-28—FIELD
CIRCUIT TEST- AMPERAGE
DRAW
H-74.
Brush Removal
and
Inspection

Refer
to Fig. H-29.

The
brushes can be removed and inspected while
the alternator is in the vehicle.

a.
Disconnect the plug to the field terminal. b. Remove the two screws and brush cover.
c. Remove brushes.
d.
Inspect brushes for excessive wear and proper
tension. The brushes can be installed by reversing
the above procedure.

H-75.
Brush Insulation
and
Continuity Test

Refer
to Fig. H-30.

a.
Connect leads of a 12-volt
test
lamp to field
FIG.
H-29—BRUSH
REMOVAL

1—
Screw

2—
Cover

3—
Brush
and
Holder
Assembly
4—
Alternator
197

H

ELECTRICAL
SYSTEM
FIG.
H-38—WIRE
COLOR CODE
AND

LOCATIONS
FOR
ALTERNATOR HOOK-UP

1— Regulator (Auxiliary)
Terminal
(Cable —
Grey)

2— Output
Terminal:
(Red)

3—
Regulator
Terminal
(Cable —
Grey)

4—
Ground
Terminal
(Cable — Black-White
Tracer)
5—
Field
Terminal
(Cable — Green-White
Tracer)

6—
Ground
(Optional)
Terminal
(Cable — Black-White
Tracer)
REAR
VIEW

35
AMP.
ALTERNATOR
REAR
VIEW
40
& 55 AMP.
ALTERNATOR
given in Par. H-78, adjusting the fan belt to its
proper tension after the alternator is mounted, as described in Par. C-27. Wires should be connected
as shown in Fig. H-38.

When
the vehicle is equipped with a radio, a .55
mfd. capacitor is required on the alternator. Mount
the capacitor strap to a ground terminal and con­
nect the lead to the output terminal.
H-88.
STARTING
SYSTEM
SERVICE
H-89.
Ignition
Switch

The
ignition switch serves both to energize the
ignition system and
engage
the starter switch.
The
ignition switch has four positions: (1) AC­

CESSORY,
(2)
LOCK,
(3) ON, and (4)
START. The
key must be in the switch to turn it to any position other than
LOCK,
and the key can be
removed only in the
LOCK
position.
In "ACC",
a connection is made from the battery

terminal
to the accessory terminal of the switch to
allow accessories such as the radio, blower and/or
windshield wiper to be operated with the ignition, fuel
gauge
and indicator light circuits off.
In "LOCK",
no accessory supplied through the
ignition switch can be operated. Also, the ballast
resistor (V-6
engine
only) circuit to the ignition
coil
(IGN) is grounded.
In
"ON", a connection is made from the battery

terminal
to the accessory terminal so that all
ignition switch supplied accessories can be operated. Also the battery is connected to the ballast resistor
(V-6
engine
only) leading to the ignition coil

(IGN).
From
this same terminal, a lead
into
the
instrument cluster energizes the fuel
gauge
and
indicator lights.
In "START",
all ignition switch supplied acces­
sories are temporarily disconnected. A connection is made to the starter solenoid lead. The charge

and
oil indicator lamps
will
light until the
engine
is started.
H-90.
Ignition
Switch
Removal

a.
Remove the bezel nut and pull back the main
switch body.
Lower
the switch
body
from under the instrument panel so that the wiring harness plug

can
be removed from the prong connection,
b. If the lock cylinder is to be removed, turn the
ignition key to the right and insert a short
piece

of wire or end of a paper clip
into
the lock release

hole
in the switch body. Pressing on the lock
cyl­
inder retainer
will
allow the cylinder to be removed.
H-91.
Ignition
Switch
Installation

Before installing the lock cylinder
into
the main
switch body,
note
the position of the lock cylinder
retainer.

a.
Place the lock cylinder
into
the main switch
body
with the highest part of the lock cylinder
retainer in line with the lock release
hole
in the
main
switch body.
b. Compress the lock cylinder retainer so that the
lock cylinder can be installed all the way
into
the

main
switch
body
or until the retainer can be

seen
through the pin hole.

c.
Install
wiring harness plug
onto
switch
body

prong connection.

d.
Install
this main switch
body
into
the instru­
ment panel opening from the
rear.

e. To make sure that the switch is in its correct position, install the ignition key in the off position.
Then
turn the switch
body
until the key is straight
up and down. Remove the key, install the bezel
nut and secure.
H-92.
PRESTOLITE
STARTING
MOTOR
DAUNTLESS
V-6 and

HURRICANE
F4
ENGINE

The
Prestolite starting motor on the V6
engine
is

similar
in construction (with exception of pinion housings) to the starting motor installed on F4

engines.
The
starter solenoid switch is bolted to the starter
frame.

The
starter is equipped with
sealed-type
absorbent
bronze bearings and no lubricant is required. Service procedures for the Prestolite starter are
given in
Pars.
H-93 to H-107. 202