1988 JEEP CHEROKEE charging

be obtained. During high speeds "on" time may be 10 percent and "off"
time 90 percent. During low speeds with high electrical loads, "on"
time may be 90 percent and "off" time 10 percent.
SI SERIES
A rectifier bridge, connected to stator windings, contains 6
diodes (3 positive and 3 negative) molded into an assembly. This
rectifier bridge changes stator AC voltage into DC voltage, which
appears at output terminal.
Alternator field current is supplied through a diode trio
which is also connected to stator windings. A capacitor is mounted to
end frame, protecting rectifier bridge and diodes from high voltage
and suppressing radio interference noise.
TROUBLE SHOOTING
NOTE: See the TROUBLE SHOOTING - BASIC PROCEDURES article
in the GENERAL TROUBLE SHOOTING section.
TESTING
PRELIMINARY INFORMATION
NOTE: Before making electrical checks, visually inspect all
terminals for clean, tight connections. Check alternator
mounting bolts and drive belt tension. Battery must be in
good condition to test charging system.
TESTING (ON-VEHICLE)
CS SERIES
Over/Undercharged Battery (W/ STandard Instruments)
1) If an overcharging condition is suspected, run engine at a
moderate speed. Connect a voltmeter across battery terminals. If
voltmeter indicates more than 16 volts, replace alternator.
2) If an undercharging condition is suspected, disconnect
2
wire connector from alternator. Turn ignition on with engine off.
Connect a voltmeter between terminal "L" in wiring harness and ground.
Record reading.
3) If terminal "I" is used, connect voltmeter between
terminal "I" and ground. Record reading. If voltmeter reads battery
voltage, circuits are okay. If voltmeter reads zero, this indicates an
open circuit between terminal checked and battery. Repair as
necessary.
Overcharged Battery (W/ Gauges)
If an overcharging condition is suspected, run engine at a
moderate speed. Connect a voltmeter across battery terminals. If
voltmeter indicates more than 16 volts, replace alternator.
Alternator Output Test (W/ Standard Instruments Or Gauges)
1) Run engine at moderate speed, all electrical accessories
off. Measure voltage across battery, if above 16 volts, replace
alternator.
2) Connect an ammeter in circuit at "BAT" terminal of
alternator. Turn on all available accessories. Connect a battery load
tester across battery. Operate engine at 2000 RPM and adjust battery
load tester as required to obtain maximum current output while

maintaining 13 volts or more.
3) Output must be within 15 amps of rated output stamped on
alternator. If output is not within 15 amps of rated output, replace
alternator.
SI SERIES
Overcharged Or Undercharged Battery
1) If an overcharging condition is suspected, attach a
voltmeter across battery terminals. Run engine at a moderate speed
with all accessories off. If voltmeter reads 15.5 volts or more,
remove alternator for repair.
2) If an undercharging condition is suspected, turn ignition
on. Connect a voltmeter from alternator "BAT" terminal to ground.
Voltmeter should read 12 volts. Connect voltmeter between No. 1
terminal and ground. Voltmeter should read one volt or more.
3) Connect voltmeter between No. 2 terminal and ground.
Voltmeter should read 12 volts. A zero reading on any connection
indicates an open between connection and battery. Opens in the No. 2
lead may be between terminals at the crimp between harness wire and
terminal, or in wire.
Alternator Output Test
1) Connect an ammeter in circuit at "BAT" terminal of
alternator. Turn on all available accessories. Connect a carbon pile
across battery. Operate engine at 2000 RPM and adjust carbon pile as
required to obtain maximum current output.
2) Ampere output must be within 10 amps of rated output. If
output is not within 10 amps of rated output, ground field winding by
inserting a screwdriver into test hole. Repeat step 1).
3) If output is increases to within 10 amps of rated output
with field grounded, regulator is defective. If output remains below
10 amps of rated output, check field winding, diode trio, rectifier
bridge, and stator.
CAUTION: Tab is within 3/4" of casting surface. DO NOT force tool
beyond 1" into end frame. If test hole is not accessible,
proceed to BENCH TESTING.
BENCH TESTING
NOTE: There are no internal checks for CS series alternators.
SI SERIES
Rotor Field Winding Test
1) To check for grounds, attach ohmmeter leads to shaft and
slip ring (each ring in turn). If reading is not infinity, replace
rotor.
2) To test for open field, attach ohmmeter leads to each slip
ring. Resistance should measure about 2.4
2.8 ohms on 12SI series, or
1.72.1 ohms on 17SI series. If not, replace rotor.

volts, check charging system.
KEYPAD TEST FAILURE
1) If KEYPAD TEST FAILURE message is displayed, disconnect
DRB-II from transmission diagnostic connector. DO NOT touch keys on
DRB-II keypad. Reconnect DRB-II to transmission diagnostic connector
and note display.
2) If KEYPAD TEST FAILURE message is not displayed, proceed
with diagnostics. If KEYPAD TEST FAILURE message is displayed, replace
DRB-II and proceed with diagnostics.
LOW BATTERY
If LOW BATTERY message is displayed, use external voltmeter
to check battery voltage at battery terminals. If battery voltage is
11.7-13.0 volts, replace DRB-II. If battery voltage is not 11.7-13.0
volts, check charging system.
RAM TEST FAILURE
1) If RAM TEST FAILURE message is displayed, disconnect DRB-
II from transmission diagnostic connector. DO NOT touch keys on DRB-II
keypad. Reconnect DRB-II to transmission diagnostic connector and note
display.
2) If RAM TEST FAILURE message is not displayed, proceed with
diagnostics. If RAM TEST FAILURE message is displayed, replace DRB-II
and proceed with diagnostics. If KEYPAD TEST FAILURE message is
displayed, replace DRB-II and proceed with diagnostics.
COMPONENT TESTING
BRAKE SWITCH
Brake switch is mounted above brake pedal. When brake pedal
is operated, brake switch delivers an input signal to TCM. The TCM
uses input signal for controlling No. 3 valve body solenoid for torque
converter lock-up. No other information is available from
manufacturer.
NOTE: For proper brake switch adjustment, see BRAKE SWITCH under
REMOVAL & INSTALLATION .
NEUTRAL SAFETY SWITCH
NOTE: Neutral safety switch may be referred to as park/neutral or
gear select switch. For proper neutral safety switch
adjustment, see NEUTRAL SAFETY SWITCH under REMOVAL &
INSTALLATION.
Disconnect electrical connector. Note terminal
identification. See Fig. 4. Using ohmmeter, check continuity between
specified terminals in relation to shift lever position. See NEUTRAL
SAFETY SWITCH CONTINUITY SPECIFICATIONS table. Replace neutral safety
switch if continuity is not as specified.
NEUTRAL SAFETY SWITCH CONTINUITY SPECIFICATIONS









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Shift Lever Continuity
Position Between Terminals

hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... (1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Inoperative ............. A ........ ( 2) Require replacement.
Leaking (vacuum) ........ A .. Require repair or replacement.
Linkage bent,
affecting performance .. A ... Require repair or replacement
of linkage.
Linkage bent, not
affecting performance .. 2 ... Suggest repair or replacement
of linkage.
Linkage binding,
affecting performance .. A ... Require repair or replacement
of linkage.
Linkage binding, not
affecting performance .. 1 .. Suggest repair or replacement
of linkage.
Linkage broken .......... A ... Require repair or replacement
of linkage.
Linkage loose, affecting
performance ............ A ... Require repair or replacement
of linkage.
Linkage loose, not
affecting performance .. 1 ... Suggest repair or replacement
of linkage.
Linkage missing ......... C ............ Require replacement.
Linkage noisy ........... 2 .. Suggest repair or replacement.
Missing ................. C ............ Require replacement.
Noisy ................... 2 .. Suggest repair or replacement.
Out of adjustment ....... A .. Require repair or replacement.
( 1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Inoperative includes intermittent operation or out of
OEM specification.









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AIR BAGS
For all air bag components and conditions, refer to vehicle
manufacturer's specifications for diagnosis and parts replacement.
ALTERNATORS AND GENERATORS
NOTE: If components have been added that increase vehicle
electrical load requirement (for example, sound systems,
air conditioning, alarm systems, etc.), charging system
output must meet the increased demand.
ALTERNATOR AND GENERATOR INSPECTION









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Condition Code Procedure
Alternator output meets
OEM specification but is
insufficient for add-on

Post (top or side)
loose .................. A ............ Require replacement.
Post (top or side) melted,
affecting performance .. A ........... (6) Require repair or
replacement.
Post (top or side) melted,
not affecting
performance ............ 2 ........... ( 6) Suggest repair or
replacement.
Specific gravity low .... B .......... ( 7) Further inspection
required.
State of charge low ..... A .......... ( 7) Further inspection
required.
Top dirty ............... 2 ....... Suggest cleaning battery.
Top wet ................. A ... ( 8) Require cleaning battery.
Further inspection required.
Vent cap loose .......... A ... Require repair or replacement
of vent cap.
Vent cap missing ........ C .......... Require replacement of
vent cap.
( 1) - DO NOT attempt to charge a frozen battery. Allow battery
to warm thoroughly and then performance-test. If battery
fails performance test, require replacement.
( 2) - No service suggested or required unless the battery fails
performance test, in which case, require replacement.
( 3) - This phrase refers to a battery that fails to either
accept and/or retain a charge using appropriate times
listed in the Battery Charging Guide of the BCI Service
Manual, battery charger operating manual, or battery
manufacturer's specifications.
( 4) - Determine cause of low fluid level. Refill to proper
level(s) with water (distilled water preferred). Recharge
battery and performance-test. If battery does not meet
specifications, require replacement. If battery is sealed
type (non-removable filler caps), require replacement.
( 5) - The battery may meet battery manufacturer's specifications
but test below the minimum specification defined by the
vehicle's OEM for that vehicle.
( 6) - Determine cause and correct prior to repair or replacement
of part.
( 7) - Recharge and test to manufacturer's specifications. If
battery fails performance test, require replacement.
( 8) - Check fluid level and adjust to manufacturer's
specification. Suggest checking charging system for
proper operation.









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BATTERY CABLES
See BATTERY CABLES, WIRES AND CONNECTORS .
BATTERY CABLES, WIRES AND CONNECTORS
BATTERY CABLE, WIRE AND CONNECTOR INSPECTION








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Condition Code Procedure
Application incorrect ... B .. Require repair or replacement.
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware

Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Wire lead burned ........ A .. Require repair or replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.
(1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Malfunctioning includes inoperative, intermittent
operation, or failure to perform all functions.
( 3) - Make sure poor sound quality is not caused by
ignition/charging system or other forms of electrical
interference.









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RELAY BOXES
RELAY BOX INSPECTION








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Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Broken, affecting
performance ............ A ............ Require replacement.
Broken, not affecting
performance ............ .. ........ No service suggested or
required.
Burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Burned, not affecting
performance ............ 2 ........... ( 1) Suggest repair or
replacement.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Cover missing ........... C ... Require replacement of cover.
Cracked, affecting
performance ............ A .. Require repair or replacement.
Cracked, not affecting
performance ............ 1 .. Suggest repair or replacement.
Melted, affecting
performance ............ A ........ ( 1) Require replacement.
Melted, not affecting

See HORNS AND SIRENS .
SOLENOIDS
See ACTUATOR MOTORS (SOLENOIDS) (ELECTRIC) .
NOTE: For starter solenoids that are integral to the starter
assembly, see STARTERS.
NOTE: For starter relays, see RELAYS.
SPEAKERS AND MICROPHONES
SPEAKER AND MICROPHONE INSPECTION








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Condition Code Procedure
Application incorrect ... A ............ Require replacement.
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Inoperative ............. B ........... ( 2) Require repair or
replacement. Further
inspection required.
Membrane torn ........... A ............ Require replacement.
Missing ................. C ............ Require replacement.
Polarity reversed ....... A ................. Require repair.
Sound quality poor ...... A ........... ( 3) Require repair or
replacement. Further
inspection required.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
( 1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Inoperative includes intermittent operation or out of
OEM specification.
( 3) - Make sure poor sound quality is not caused by
ignition/charging system or other forms of electrical

broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector melted ........ A ........... (1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Malfunctioning .......... A ........... ( 2) Require repair or
replacement.
Missing ................. C ............ Require replacement.
Skips ................... A .. Require repair or replacement.
Sound quality poor ...... A ........... ( 3) Require repair or
replacement.
Speed incorrect ......... A .. Require repair or replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Wire lead burned ........ A .. Require repair or replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.
( 1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Malfunctioning includes inoperative, intermittent
operation, or failure to perform all functions.
( 3) - Make sure poor sound quality is not caused by
ignition/charging system or other forms of electrical
interference.









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TENSIONERS
TENSIONER INSPECTION








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Condition Code Procedure
Alignment incorrect ..... B .. Require repair or replacement.
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement