Testing—Off-Vehicle; Alternator Noise; Visual Inspection; Battery Discharge Through Alternator - Jeep J-10 Series 1982 Technical & Service Manual

1E-4 CHARGING SYSTEM
Visual Inspection
Inspect for clean and tight cable terminal connections
at the battery posts, engine block, and starter motor
solenoid. Inspect for corrosion and loose wire terminal
connections at the alternator, starter motor solenoid,
dash panel connector and the charging system indicator
(i.e., ammeter or voltmeter). Inspect all wires for
cracked or broken insulation. Ensure the alternator
mounting screws are tight and that it is properly
grounded. Inspect the electrolyte level in the battery and
add water if necessary. Test the alternator drive belt
tension.
Alternator Noise
Unusual alternator noise may be caused by any one or
more of the following conditions:
• Loose mounting bolts.
• Loose or misaligned pulley.
• Worn or dirty bearings.
• Out-of-round or rough slip rings.
• Defective brushes.
• Shorted rectifier diode(s) (indicated by a high fre
quency whine).
Noise from the cooling system can also sound like
alternator noise. Disconnect and plug the heater hoses to
eliminate the possibility of the alternator bracket repro
ducing heater core noises.
Faulty Ammeter orVoltmeter Operation
Diagnosis of the instrumentation circuits is described
in Chapter 1L—Power Plant Instrumentation.
Overcharged/Undercharged Battery
For battery undercharged-overcharged diagnosis, re
fer to DARS charts 1 and 2.
Battery Discharge Through Alternator
If the alternator is suspected of discharging the bat
tery because of excessive current leakage, perform the
following test procedure with a No. 158 bulb and bulb
socket with attached jumper wires.
WARNING: Failure to disconnect battery negative
cable before disconnecting alternator output wire can
result in injury.
(1) Disconnect battery negative cable. Disconnect
output wire (red) from alternator.
(2) Connect test bulb jumper wires in series with
output wire and alternator output terminal. Connect
battery negative cable. Bulb should not light. If bulb
lights (even dimly), replace bridge rectifier.
(3) Disconnect battery negative cable and remove
jumper wires.
(4) Disconnect wires from No. 1 and 2 terminals of
alternator.
(5) Connect test bulb jumper wires in series with
No. 1 terminal at alternator and the battery positive
post. Connect battery negative cable. Bulb should not
light. If bulb lights (even dimly), test diode trio. If diode
trio is not defective, replace voltage regulator.
(6) Connect test bulb jumper wires in series with
No. 2 terminal at alternator and battery positive post.
Bulb should not light. If bulb lights (even dimly), replace
voltage regulator.
TESTING—OFF-VEHICLE
Rotor (Field) Winding Short-to-Ground Test
To perform this test, remove the rotor and front hous
ing assembly from the stator and rear housing assem
bly. Refer to Alternator Overhaul for procedure.
Perform the test with an ohmmeter set for the xlOOO
ohm scale or with a 110-volt test lamp.
Touch one test lead probe to rotor shaft and touch
other probe to one slip ring (fig. 1E-4). Repeat with the
other slip ring. In each test, the ohmmeter should in
dicate infinite resistance (no pointer movement) or the
test lamp should not light.
Test Results
If the ohmmeter indicates other than an infinite re
sistance or test lamp lights, a short to the rotor shaft
exists. Inspect the soldered connections at the slip rings
to ensure they are secure and not shorted to the rotor
shaft, or that excess solder is not shorting rotor winding
to the shaft. Replace the rotor if defective.
OHMMETER
SET SELECTOR
ATX1000
/0155
Hg. 1E-4 Rotor (Field) Winding Short-to-Ground Test
Rotor (Field) Winding Open Test
To perform this test, remove the rotor and front hous
ing assembly from the stator and rear housing assem
bly. Refer to Alternator Overhaul for procedure.