1988 JEEP CHEROKEE Service Repair Manual

Fig. 2: Rotor Bench Test For Open or Short Circuit
Stator Test
NOTE: Delco 17SI alternator has delta stator windings and cannot
be checked for open circuit.
1) For 12SI series alternator, measure resistance between
stator leads. See Fig. 3. If reading is not infinity, replace stator.
2) On all models, connect ohmmeter leads to any stator lead
and to stator frame. Ohmmeter reading should be infinity. See Fig. 3.

Fig. 3: Testing Stator for Open or Grounded Circuits
Diode Trio Test
1) Remove diode trio from end frame. Connect an ohmmeter to
single connector and to one of the 3 connectors. See Fig. 4. Note

reading and reverse leads. If readings are the same, replace diode
trio.
2) A good diode trio will give a high and low reading. Repeat
tests between single connector and each of the 3 connectors. Connect
ohmmeter to each of the 3 connectors. If any readings are zero,
replace diode trio.
NOTE: Before replacing diode trio, also check rectifier bridge.
DO NOT use high voltage, such as 110
volt test light, when
testing diode trio.
Fig. 4: Bench Testing Diode Trio
Rectifier Bridge Test
1) Position ohmmeter with one lead touching grounded heat
sink and the other lead touching flat metal on one of the 3 terminals

or threaded studs. Observe reading and reverse test lead connections.
See Fig. 5 .
2) If both readings are the same, replace rectifier bridge. A
good bridge will give a high and low reading. Retest all terminals (6
tests with insulated heat sink).
3) Connect test leads to insulated heat sink and one edge of
the 3 terminals. Observe reading and reverse connections. Repeat test
on all terminals (6 tests with insulated heat sink).
4) When all 12 tests have been made, testing is complete. DO
NOT use high voltage light to check bridge. DO NOT replace diode trio
or rectifier bridge unless at least one pair of readings is the same
(with leads reversed).
Fig. 5: Bench Testing Rectifier Bridge
OVERHAUL
NOTE: There are no overhaul procedures for CS130 alternators.
INSPECTION
Wash all metal parts except bearings, stator and rotor.
Inspect rotor slip rings. They may be cleaned with 400 grit or finer

polishing cloth, while rotor is being rotated. Slip rings may be lathe
turned to .002" (.05 mm) maximum indicator reading.
Slip rings are not replaceable. Excessive damage will require
rotor replacement. Inspect brushes for wear, replacing them if more
than 50% worn.
Fig. 6: Exploded View of Model 12SI Alternator
Courtesy of General Motors Corp.

Fig. 7: Exploded View of Model 17SI Alternator
Courtesy of General Motors Corp.
SPECIFICATIONS
ALTERNATOR OUTPUT FOR CS SERIES








\









\









\









\









\









\

Stamped Rating Amps @ 14v Engine RPM
85 .................. 30 ..................... 1600
100 ................. 36 ..................... 1600
105 ................. 42 ..................... 1600









\









\









\









\









\









\

ALTERNATOR OUTPUT FOR SI SERIES








\









\









\









\









\









\

Stamped Rating Amps @ 14v Engine RPM
66 .................. 23 ..................... 1600
78 .................. 30 ..................... 1600
94 .................. 30 ..................... 1600
120 ................. 50 ..................... 1600









\









\









\









\









\









\

\003
AN TI- L O CK B RAK E S A FE TY P R EC AU TIO NS

1988 J e ep C hero ke e
GENERAL INFORMATION
Anti-Lock Brake Safety Precautions
* PLEASE READ THIS FIRST *
This article is intended for general information purposes
only. This information may not apply to all makes and models. If
vehicle is equipped with Anti-Lock Brake System (ABS), refer to
appropriate ANTI-LOCK BRAKE SYSTEM article in the BRAKES section for
description, operation, depressurizing, testing, system bleeding,
trouble shooting and servicing of specific system.
WARNING: Failure to depressurize ABS could lead to physical injury.
ANTI-LOCK BRAKE SAFETY PRECAUTIONS
WARNING: Failure to depressurize ABS could lead to physical injury.
* NEVER open a bleeder valve or loosen a hydraulic line
while ABS is pressurized.
* NEVER disconnect or reconnect any electrical connectors
while ignition is on. Damage to ABS control unit may result.
* DO NOT attempt to bleed hyudarulic system without first
referring to the appropriate ANTI-LOCK BRAKE SYSTEM article
in the BRAKES section.
* Only use specially designed brake hoses/lines on ABS equipped
vehicles.
* DO NOT tap on speed sensor components (sensor, sensor rings).
Sensor rings must be pressed into hubs, NOT hammered into
hubs. Striking these components can cause demagnetization or
a loss of polarization, affecting the accuracy of the speed
signal returning to the ABS control unit.
* DO NOT mix tire sizes. Increasing the width, as long as tires
remain close to the original diameter, is acceptable. Rolling
diameter must be identical for all 4 tires. Some
manufacturers recommend tires of the same brand, style and
type. Failure to follow this precaution may cause inaccurate
wheel speed readings.
* DO NOT contaminate speed sensor components with grease. Only
use recommended coating, when system calls for an
anti-corrosion coating.
* When speed sensor components have been removed, ALWAYS check
sensor-to-ring air gaps when applicable. These specifications
can be found in each appropriate article.
* ONLY use rocommended brake fluids. DO NOT use silicone brake
fluids in an ABS equipped vehicle.
* When instlling transmittion devices (CB's, telephones, etc.)
on ABS equipped vehicles, DO NOT locate the antenna near the
ABS control unit (or any control unit).
* Disconnect all on-board computers, when using electric
welding equipment.
* DO NOT expose the ABS control unit to prolonged periods of
high heat (185
F/85C for 2 hours is generally considered a
maximum limit).