charging JEEP CHEROKEE 1988 Service Repair Manual

1) If all components have been checked and/or repaired, but
a system failure or problem still exists, the ECU may be at fault.
However, the ECU is a very reliable unit and must always be the final
component replaced if a doubt exists concerning the cause of a system
failure.
2) The only way to confirm an ECU malfunction is to take the
unit to an AMC dealer to have it tested. This is the only sure way to
avoid replacing a good ECU.
SYSTEM DIAGNOSIS
PRELIMINARY CHECKS
Be sure fuel is actually reaching the injector. Make sure no
air is entering the intake or exhaust system above the catalytic
converter. Before assuming an engine control system malfunction,
inspect the following systems to ensure components are in good
condition and are operating properly.
* All support systems and wiring.
* Battery connections and specific gravity.
* Electrical and vacuum connections on components and sensors.
* Emission control devices.
* Ignition system.
* Vacuum hoses.
CAUTION: Never connect or disconnect a component without turning the
ignition switch off. Never apply more than 12 volts or AC
voltage to system terminals. Disconnect battery cables
before charging it. Remove ECU if temperatures are expected
to exceed 176
F (80C), such as in a paint shop bake oven.
DIAGNOSTIC TEST CHARTS
Following are 6 different diagnostic test flow charts,
providing the shortest means of testing the system. These include:
* Ignition Switch "OFF" Chart - Tests system power for ECU
memory keep-alive voltage.
* Ignition Switch "ON" Power Chart - Tests system power
function and fuel pump power function.
* Ignition Switch "ON" Input Chart - Tests closed throttle
(idle) switch, wide open throttle (WOT) switch, manifold
absolute pressure (MAP) sensor, park/neutral switch, coolant
temperature sensor (CTS), manifold air/fuel temperature (MAT\
)
sensor and the respective switch or sensor circuits.
* System Operational Chart - Tests engine start-up and fuel
injector circuits, plus function of closed loop air/fuel
mixture, coolant temperature sensor, manifold air/fuel
temperature sensor, knock sensor and closed loop ignition
retard/advance, EGR valve and canister purge solenoid, idle
speed actuator, and A/C control.
* Basic Engine Chart - Indicates possible failures within other
engine related components.
* Man. Trans. Up-shift Chart - Tests up-shift indicator lamp
function on manual transmission vehicles.

CO Carbon Monoxide 

CO2 Carbon Dioxide 

CONV Convertible 

CP Canister Purge 

CPA Connector Position Assurance 

CPS Crank Position Sensor 

CTS Coolant Temperature Sensor 

CV Check Valve or Constant Velocity 

CVC Constant Vacuum Control 

CW Clockwise 

CYL or Cyl. Cylinder 

Calif. California 

Carb. Carburetor 

Chrg. Charging 

Circ. Circuit 

Cntrl. Control 

Comp. Compressor or Compartment 

Conn. Connector 

Cont. Continued 

Conv. Convertible or Converter 

Cu. In. Cubic Inch 

Cyl. Cylinder 











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"D" ABBREVIATION TABLE
"D" ABBREVIATION TABLE







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ABBREVIATION DEFINITION 










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"D" Drive 

DBC Dual Bed Catalyst 

DC Direct Current or Discharge 

DDD Dual Diaphragm Distributor 

DERM Diagnostic Energy Reserve Module 

DFI Digital Fuel Injection 

DIC Driver Information Center 

DIS Direct Ignition System 

DIS Distributorless Ignition System 

DIST Distribution 

DISTR Distributor 

DK BLU Dark Blue 

DK GRN Dark Green 

DME Digital Motor Electronics (Motronic System) 

DOHC Double Overhead Cam 

DOT Department of Transportation 

DP Dashpot 

DRB-II Diagnostic Readout Box 

DVOM Digital Volt/Ohm Meter (see VOM) 

Def. Defogger or Defroster 

Def. Defrost 

Defog. Defogger 

Diag. Diagnostic 

Dist. Distributor or Distribution 

Dr. Door 











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"E" ABBREVIATION TABLE
"E" ABBREVIATION TABLE







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ABBREVIATION DEFINITION 

\003
A/C C O M PR ESSO R O IL C HEC KIN G

1988 J e ep C hero ke e
A/C General Servicing
COMPRESSOR OIL CHECK
* PLEASE READ THIS FIRST *
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
ISOLATING COMPRESSOR - GRAND WAGONEER ONLY
1) Connect service gauge set to the compressor service valves
and open compressor valves slightly (turn clockwise). Start engine and\
operate air conditioning. Slowly turn compressor suction valve
clockwise toward closed (front-seated) position.
2) When suction pressure is reduced to zero or less, turn off
engine and compressor and quickly turn suction valve stem in to full
front-seated position. Suction pressure should be slightly above zero.
Turn discharge valve into front-seated position.
3) To check oil lever, slowly open crankcase plug to relieve
any remaining pressure. After oil level is correct, cap service gauge
parts on both valves. Back-seat suction service valve to allow
refrigerant to enter compressor. Open discharge valve halfway.
4) Loosen discharge service valve cap, allowing refrigerant
pressure to force air out of compressor. Back-seat service valve and
tighten cap. Compressor is now ready for operation.
REFRIGERANT OIL
Only new, pure, moisture-free refrigerant oil should be used
in the air conditioning system. This oil is highly refined and
dehydrated to a point where moisture content is less than 10 parts per
million. The oil container must be tightly closed at all times when
not in use, or moisture will be absorbed from the air and introduced
into the refrigeration system.
DISCHARGING SYSTEM
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
If compressor has stem-type service valves, it can be
isolated and removed without discharging entire system. Otherwise,
discharge system completely using approved refrigerant
recovery/recycling equipment before loosening any fittings.
DISCONNECTING LINES & FITTINGS
After system is discharged, carefully clean area around all
fittings to be opened. Always use 2 wrenches when tightening or
loosening fittings to avoid twisting or distorting lines. Cap or plug
all openings as soon as lines are removed. Do not remove caps until
immediately before connections are made. This will keep entry of air
and moisture to a minimum, reducing the chance of damage to
components.

\003
A/C -H EA TE R S YSTE M - M AN UAL

1988 J e ep C hero ke e
1988 Manual A/C-Heater Systems
JEEP
* PLEASE READ THIS FIRST *
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
DESCRIPTION
On Cherokee, Comanche and Wagoneer, the Climate Control
System is an integral assembly combining air conditioning, heating and
ventilating capabilities for models with air conditioning. The A/C
registers are built into instrument panel.
On Wrangler models, a dual flow unit with the capability of
recirculating air or drawing air from outside is used. It incorporates
under-dash registers and uses a blend-air type system.
The A/C components include a compressor, condenser, receiver-
drier, a sight glass (in the receiver-to-evaporator line) and
evaporator housing. Evaporator housing contains evaporator core,
expansion valve, thermostat, wiring and drain tube. Blower motor and
fan are located in blower housing, which is attached to evaporator
housing.
Vents provided in evaporator housing are adjustable to direct
air to different positions in vehicle's interior. System controls
include fan and temperature control knobs built into lower evaporator
housing assembly or temperature and mode levers on control panel
integrated with instrument panel.
OPERATION
A/C SYSTEM CONTROLS
Temperature & Fan Control Knobs
(Wrangler)
The right rotary control knob allows selection of desired
temperature. Knob has "OFF" "1", "2" and "3" positions for different
levels of cooling. The left rotary fan switch (knob) controls blower
motor speed. Knob has "OFF", "LOW", "MED" and "HI" positions. Fan will
operate unless mode control lever is in "OFF" position.
The A/C fan switch is a 3-speed unit used in conjunction with
a blower motor resistor. Fan switch controls low, medium and high
speed operation. Switch may be serviced by removing access plate
located on lower evaporator core housing, below control panel.
The A/C temperature control switch has a thermostat unit
built-in. Cooling adjustment is done by turning knob in a clockwise
rotation. For fast, efficient system operation in hot weather, vehicle
should be purged of hot air by driving about 2-3 city blocks with at
least one window open. During this time, temperature control knob
should be rotated clockwise to "MAX" position and fan control knob
placed in "HI" position. This allows evaporator to pre-cool and avoid
typical first blast of warm air.
Temperature Control Panel
(Cherokee, Comanche & Wagoneer)
The upper temperature control (mode) lever includes "MAX",
"NORM", "BI-LEVEL", "VENT", "HEAT" and "OFF" positions. At the far end

service to the system in question, if the repair creates
or continues an unsafe condition.
Reasons to Suggest Repair or Replacement
1 - Part is close to the end of its useful life (just above
discard specifications, or weak; failure likely to occur
soon, etc.)
2 - To address a customer need, convenience, or request (to
stiffen ride, enhance performance, eliminate noise,
etc.)
3 - To comply with maintenance recommended by the vehicle's
Original Equipment Manufacturer (OEM)
4 - Technician's recommendation based on substantial and
informed experience
NOTE: Suggested services are always optional. When presenting
suggested repairs to the customer, you must present the
facts, allowing the customer to draw their own conclusions
and make an informed decision about how to proceed.
HEATING, VENTILATION, AND AIR CONDITIONING
SERVICE PROCEDURES REQUIRED AND SUGGESTED FOR PROPER VEHICLE
OPERATION
CAUTION: Before working on any air conditioning system, be sure
to review current local, state, federal, and EPA
regulations regarding charging, recycling, and disposal
of refrigerant.
ACCUMULATORS
ACCUMULATOR 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.
Beyond vehicle
manufacturer's service
interval ............... 3 ............ Suggest replacement.
Dessicant at the end of
its useful life (saturated
with moisture) ......... 1 .. Suggest repair or replacement.
Dessicant bag
deteriorated ........... A ........ ( 1) Require replacement.
Further inspection required.
Leaking ................. A .. Require repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Tubing connection
leaking ................ A .. Require repair or replacement.

\003
A/C S YSTE M G EN ER AL S ER VIC IN G

1988 J e ep C hero ke e
1988 AIR CONDITIONING & HEAT
A/C General Servicing
Diagnostic Procedures
Eagle & Jeep
* PLEASE READ THIS FIRST *
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
INTRODUCTION
This article is to be used for general service and diagnosis.
For specific repair or replacement procedures, use the appropriate
repair article in this section.
R-12 REFRIGERANT - SAFETY PRECAUTIONS
1) Always work in a well-ventilated, clean area. Refrigerant
(R-12) is heavier than oxygen, and will displace oxygen in a confined
area. Always wear eye protection when working around air conditioning
systems and R-12. The system's high pressure can cause severe injury
to eyes and skin if a hose were to burst. R-12 evaporates quickly
when exposed to atmosphere, freezing anything it contacts.
2) Use care when handling refrigerant containers. Do not
drop or strike containers. Do not expose refrigerant containers to
excessive heat. Containers must never be heated more than 125
F.
Never expose R-12 directly to open flame.
CAUTION: When R-12 is exposed to an open flame, drawn into a running
engine, or detected with a Halide (propane) leak tester,
poisonous phosgene gas is formed. Keep work areas
ventilated and keep vehicles with running engines away.
USING INDIVIDUAL R-12 CANS
Disposable refrigerant cans (referred to as one pound cans)
have a flat type seal or a screw type seal, and the proper can tap
must be used for each type. Be sure sealing gasket on can tap is in
good condition. A proper safety can tap will prevent refrigerant from
flowing back into open can, as the tap has a one-way flow control.
NOTE: Recent findings by the EPA indicate that R-11, R-12 and
R-113 are harmful to the Earths' protective Ozone layer.
Make every attempt possible, to avoid discharging R-11, R-12
or R-113 into the atmosphere.
USING MULTI-CAN DISPENSING VALVES
A multi-can dispensing valve allows the attachment of
several cans of refrigerant, and is a good substitute when a bulk
container is not available. Cans are installed onto each leg of the
multi-can dispensing valve in the same manner as the individual cans,
and each leg has its own can tap.

Fig. 3: Assembling Ford Spring-Coupling Fitting
3) Lubricate both sides of fitting with clean refrigeration
oil. Assemble the fitting by pushing together with a slight twisting
motion. Check to make sure spring is over flared end of female
fitting.
PLACING SYSTEM IN OPERATION
After component replacement and/or system servicing has been
completed and all connections have been made, proceed as follows:
1) Evacuate the system using vacuum pump.
2) Charge the system with R-12. See REFRIGERANT CAPACITY in
the A/C SYSTEM SERVICE SPECIFICATIONS in this article.
3) Leak test the system, with particular attention to all new
connections and components.
4) Make a performance test of the system. Never assume that a
recharging has automatically corrected a problem.
DIAGNOSTIC PROCEDURES
Diagnosis is an important first step in A/C system servicing.
To save time and effort, systems should be carefully checked to
identify the causes of poor performance. By using the following
diagnostic charts, defective components or system damage can be
quickly located. To identify problems that are specific to one system,
refer to the repair sections of this article. The charts in this
article apply to all systems.
PREPARATION FOR TESTING
1) Attach Low and High side gauges.
2) Start engine and allow it to warm up.
3) Set system to COOL and blower to HIGH.
4) Open car doors and hood.
5) Run at fast idle for 2-3 minutes.

\003
ALTE R NATO R - D ELC O W /IN TE G RAL R EG ULA TO R

1988 J e ep C hero ke e
1988 Alternators & Regulators
DELCO-REMY WITH INTEGRAL REGULATOR
Jeep
DESCRIPTION
There are 2 types of alternators used on these vehicles. The
12SI and 17SI series (Systems Integral), means alternator with built-
in regulator. All 12SI alternators have "Y" stator windings, while all
17SI have delta windings.
The CS130 (Charging System) alternators have a high amperage
output. This alternator does not have a diode trio.
IDENTIFICATION
Fig. 1: Alternator Terminal Identification & Locations
"S" terminal is optional on CS130.
OPERATION
CS SERIES
Regulator voltage varies to compensate for temperature.
Voltage is regulated by controlling rotor field current. Regulator
switches rotor field current "on" and "off" at a fixed frequency of
approximately 400 cycles per second.
By controlling "on" and "off" time correct system voltage can

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.