1988 JEEP CHEROKEE heater
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![JEEP CHEROKEE 1988 Service Repair Manual \
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Compressor Runs Rough
* Incorrect oil or re](/manual-img/16/57037/w960_57037-113.png "JEEP CHEROKEE 1988 Service Repair Manual \
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Compressor Runs Rough
* Incorrect oil or re")
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Compressor Runs Rough
* Incorrect oil or refrigerant level.
* Internal compressor damage.
Compressor Intermittent or Inoperative
* Drive belt slipping.
* Faulty clutch air gap.
* Clutch coil wiring broken or frayed.
Noisy Compressor
* Mounting bolts loose.
* Clutch slipping.
* Improper charge in system.
* Bad clutch or pulley bearings.
* Incorrect oil level.
* Valve plate damaged.
* Piston slap.
Excessive Vibration
* Incorrect belt tension.
* Clutch loose.
* Pulley misaligned.
* System overcharged.
A/C Air Flow Stops on Acceleration
* Defective vacuum storage tank.
* Vacuum line separated or defective.
* Vacuum switch defective.
* Vacuum leak.
High Suction Pressure with Very Low Discharge Pressure
* Valve plate or gasket broken or deformed.
Very Low Suction and Discharge Pressure
* Low refrigerant charge.
* Compressor leak.
* System leak.
Heater Control Valve Does Not Close with Vacuum Applied
* Faulty heater control valve.
No Vacuum at Heater Control Valve with Lever at Extreme Left
* Vacuum source hose disconnected.
* Leaking vacuum hose.
* Faulty check valve.
* Control panel switch defective or misadjusted.
Frozen Evaporator Core
* Faulty thermostat.
* Thermostat capillary tube improperly installed.
* Thermostat not adjusted properly.
Condensation Dripping in Passenger Compartment
* Drain hose plugged or improperly installed.
* Insulation missing or improperly installed.
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TESTING
Note: The following test applies to all Jeep models except Cherokee
and Wagoneer.
Page 117 of 1378
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* A /C -H EA TE R S YSTE M U NIF O RM IN SPEC TIO N G UID ELIN ES *
1 988 J e ep C hero ke e
GENERAL INFORMATION
A/C-Heater System Motorist Assurance Program
Standards For Automotive Repair
All Makes and Models
INTRODUCTION TO MOTORIST ASSURANCE PROGRAM (MAP)
CONTENTS
Motorist Assurance Program (MAP)
OVERVIEW
OVERVIEW OF SERVICE REQUIREMENTS & SUGGESTIONS
Heating, Ventilation and Air Conditioning
ACCUMULATORS
ACTUATORS (ELECTRICAL)
ACTUATORS (VACUUM)
AIR CONDITIONING FITTINGS
AIR CONDITIONING HOSES
AIR CONDITIONING METAL LINES, HOSES AND FITTING ASSEMBLIES
AIR CONTROL DOORS
AIR DAMS (EXTERNAL)
AIR DISTRIBUTION SYSTEM
BELTS
BLEND DOORS
BLOWER FANS (BLOWER WHEEL OR SQUIRREL CAGE)
BLOWER MOTORS
BLOWER RESISTORS
BLOWER SWITCHES
CABIN AIR FILTERS
CIRCUIT BREAKERS
COMPRESSOR CLUTCH ASSEMBLIES
COMPRESSORS
CONDENSER AIR SEALS
CONDENSER FAN MOTORS
CONDENSERS
CONNECTORS
CONTROL CABLES
CONTROL HEADS (FUNCTION SELECTORS)
CONTROL LINKAGES
CONTROL MODULES
COOLANT
COOLING FAN BLADES
COOLING FAN CLUTCHES
COOLING FAN MOTORS
EVAPORATOR DRAIN TUBES
EVAPORATOR PRESSURE REGULATORS (EPRS)
EVAPORATORS
EXPANSION VALVES
FUNCTION SELECTORS
FUSES, FUSIBLE LINKS AND CIRCUIT BREAKERS
FUSIBLE LINKS
GASKETS
HEATER CASES
HEATER CONTROL VALVES
HEATER CORES
Page 118 of 1378
HEATER HOSES
HIGH PRESSURE RELIEF VALVES (HPRV)
IDLERS
IN-LINE FILTERS
METAL FITTINGS
METAL LINES
MIX AND AIR CONTROL DOORS (BLEND DOORS)
O-RINGS
ORIFICE TUBES
PILOT-OPERATED ABSOLUTES (POAS)
PLENUMS
PRESSURE CONTROL VALVES
PRESSURE SENSORS
PULLEYS
RADIATORS
RECEIVER-DRIERS
REFRIGERANT
REFRIGERANT OIL
RELAYS
SEALS
SERVICE PORTS
SPRING LOCK COUPLINGS
SUCTION THROTTLING VALVES (STVS)
SWITCHES (ELECTRICAL)
TENSIONERS
THERMISTORS AND PRESSURE SENSORS
THERMOSTATS AND HOUSINGS
VACUUM HOSES AND TUBES
VACUUM RESERVOIRS
VACUUM TUBES
VALVES IN RECEIVER (VIRS)
WATER PUMPS (ELECTRIC AUXILIARY)
WIRING HARNESSES AND CONNECTORS
MOTORIST ASSURANCE PROGRAM (MAP)
OVERVIEW
The Motorist Assurance Program is the consumer outreach
effort of the Automotive Maintenance and Repair Association, Inc.
(AMRA). Participation in the Motorist Assurance Program is drawn from
retailers, suppliers, independent repair facilities, vehicle
manufacturers and industry associations.
Our organization's mission is to strengthen the relationship
between the consumer and the auto repair industry. We produce
materials that give motorists the information and encouragement to
take greater responsibility for their vehicles-through proper,
manufacturer-recommended, maintenance. We encourage participating
service and repair shops (including franchisees and dealers) to adopt
(1) a Pledge of Assurance to their Customers and (2) the Motorist
Assurance Program Standards of Service. All participating service
providers have agreed to subscribe to this Pledge and to adhere to the
promulgated Standards of Service demonstrating to their customers that
they are serious about customer satisfaction.
These Standards of Service require that an inspection of the
vehicle's (problem) system be made and the results communicated to the\
customer according to industry standards. Given that the industry did
not have such standards, the Motorist Assurance Program successfully
promulgated industry inspection communication standards in 1994-95 for
the following systems: Exhaust, Brakes, ABS, Steering and Suspension,
Engine Maintenance and Performance, HVAC, and Electrical Systems.
Further, revisions to all of these inspection communication standards
Page 141 of 1378
conductors exposed ..... A .. Require repair or replacement.
Insulation damaged,
conductors not exposed . 1 .. Suggest repair or replacement.
Missing ................. C ............ Require replacement.
Routed incorrectly ...... B ................. Require repair.
Secured incorrectly ..... B ................. Require repair.
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 replacement
of part.
( 2) - Inoperative includes intermittent operation.
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FUSIBLE LINKS
See FUSES, FUSIBLE LINKS AND CIRCUIT BREAKERS .
GASKETS
GASKET INSPECTION \
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Condition Code Procedure
Leaking ................. A ........... ( 1) Require repair or
replacement.
( 1) - Require inspection of mating and sealing surface and
repair or replace as necessary.
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HEATER CASES
See PLENUMS.
HEATER CONTROL VALVES
HEATER CONTROL VALVE INSPECTION \
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Condition Code Procedure
Application incorrect ... B ............ 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
Page 142 of 1378
of hardware.
Binding ................. 2 .. Suggest repair or replacement.
Coolant leak ............ A .. Require repair or replacement.
Disconnected ............ A .. Require repair or replacement.
Malfunctioning .......... A ........... (1) Require repair or
replacement.
Missing ................. C ............ Require replacement.
Restricted .............. A .. Require repair or replacement.
Seized .................. A .. Require repair or replacement.
Vacuum leak ............. A .. Require repair or replacement.
( 1) - Includes inoperative, intermittent operation, or
failure to perform all functions.
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HEATER CORES
HEATER CORE INSPECTION \
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Condition Code Procedure
Air flow obstruction .... A .. 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
of hardware.
Connection leaking ...... A .. Require repair or replacement.
Corroded ................ 1 .. Suggest repair or replacement.
Disconnected ............ A .. Require repair or replacement.
Fins damaged, affecting
performance ............ A .. Require repair or replacement.
Fins damaged, not
affecting performance .. .. ........ No service suggested or
required.
Internal restrictions,
affecting performance .. A .. Require repair or replacement.
Leaking ................. A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
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HEATER HOSES
HEATER HOSE INSPECTION \
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Condition Code Procedure
Application incorrect ... B ............ Require replacement.
Connected incorrectly ... A ................. Require repair.
Corroded, not reusable .. 1 ............ Suggest replacement.
Cracked ................. A .. Require repair or replacement.
Hard (brittle) .......... 1 .. Suggest repair or replacement.
Inner fabric (webbing)
damaged ................ A ............ Require replacement.
Insufficient clamping
force, allowing hose to
leak ................... A .. Require repair or replacement.
Leaking ................. A .. Require repair or replacement.
Maintenance intervals ... 3 ............ Suggest replacement.
Page 158 of 1378
2000 ....................... 27.82 ........................... 2.1
3000 ....................... 26.82 ........................... 3.1
4000 ....................... 25.82 ........................... 4.1
5000 ....................... 24.92 ........................... 5.0
6000 ....................... 23.92 ........................... 6.0
7000 ....................... 23.02 ........................... 6.9
8000 ....................... 22.22 ........................... 7.7
9000 ....................... 21.32 ........................... 8.6
10,000 ..................... 20.52 ........................... 9.4
(1) - Add correction shown to gauge readings
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OPERATIONAL TEST GAUGE READINGS
Normal System Operating Pressures (PSI) ( 1)
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Low Side High Side
Gauge Gauge
Application (Suct.) (Disc.\
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Jeep 1980-87
(Thermostatic Switch) ........ 5-24 ................... 208-250\
1988
(Accumulator Type) ........... 24-50 .................. 160-250\
( 1) - Pressure readings given are for a system in good operating
condition, at sea level and an ambient temperature of 80
F
(27C). \
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AIR CONDITIONING SYSTEM PERFORMANCE CHECK TABLE \
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PERFORM TESTS: SHOULD BE: IF: \
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Temperature Check Temperature Check is
* Switch to LOW
blower
* Close doors Too warm-Check control lever
* Check outlet 35-45
F (1.7-7.2C) operation, heater water valve,
temperature. cooling system and gauge
readings.
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Visual Check Visual Check Shows:
* Compressor Quiet, no leaks Noisy-Check belts, oil level,
seals, gaskets, reed valves.
* Condenser Free of Blocked-Clean off. Plugged-
obstructions Flush or replace.
* Receiver- Dry and warm to Frosty-Check for restriction,
Drier touch. replace desiccant.
* Sight Glass Clear or few Bubbly, foamy or streaks-
bubbles Check gauge readings.
* High Side Dry and warm to Frosty or very hot-Check for
touch. restriction or overcharge.
* Low Side Dry and cool to Frosty or warm-Check for
Lines touch. restriction, low charge or
bad valve.
Page 171 of 1378
* Switch to LOW
blower.
* Close doors. Too warm - Check control
lever operation, heater
water valve, cooling
system and gauge readings.
* Check outlet
temperature. 35-45
F (1.7-7.2 C)\
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Visual Check Visual Check Shows:
* Compressor Quiet, No Leaks Noisy - Check belts, oil
level, seals, gaskets,
reed valves.
* Condenser Free of Obstructions Blocked - Clean off.
Plugged - Flush or
replace.
* Receiver-Drier Dry and warm to Frosty - Check for re-
touch striction, replace
Desicant.
* Sight Glass Clear or few bubbles Bubbly, foamy or streaks -
Check gauge readings.
* High Side Lines Dry and warm to Frosty or very hot - Check
touch for restriction or
overcharge.
* Low Side Lines Dry and cool to Frosty or warm - Check for
touch restriction, low charge or
bad valve.
* Expansion Valve Dry Frosty - Check for moisture
or restriction. Check
sensing bulb.
* STV Dry and cool to Frosty or warm - Check
touch gauge readings for valve
malfunction.
* Evaporator Dry and cold to Freezing or warm - Check
touch expansion valve, STV or
thermo switch.
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Gauge Readings Gauge Readings are:
* High Side Gauge See Pressure Chart Above or below normal - See
A/C DIAGNOSIS.
* Low Side Gauge See Pressure Chart Above or below normal - See
A/C DIAGNOSIS.
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PRESSURE CHARTS
Page 176 of 1378
Without A/C ........................... 4.4 (4.2)
Jeep
Cherokee & Wagoneer (2)
4-Cylinder ........................... 10.0 (9.5)
V6 .................................. 12.0 (11.4)
CJ & Scrambler
4-Cylinder ............................ 9.0 (8.5)
6-Cylinder ........................... 10.5 (9.9)
Grand Wagoneer & Truck (3)
6-Cylinder .......................... 12.5 (11.8)
V8 .................................. 15.5 (14.7)
(1) - May vary +/- 15% due to system variations.
(2) - Includes 2.3 qts. (2.2L) in recovery bottle.
(3) - Includes 1 qt. (.9L) for heater.
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