JEEP CHEROKEE 1988 Service Repair Manual
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Fig. 5: Jeep Trouble Shooting Chart
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Fig. 6: Jeep Trouble Shooting Flow Chart
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Does The Blower Turn?
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\b
YES \
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NO
\b \b
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Is Air Flow Correct? Is The Fuse Blown?
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\b \
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\b
NO YES
\b \b
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Check The Air Replace The Fuse
Distribution \
\b Doors; Ensure
That There Are NO
No Obstructions \b
In The Vent
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YES Channels * Apply 12V Directly To
\b \
\b Blower Motor
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* Does The Blower Motor Turn?
* Test Drive Belt Tension
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\b * Is The Clutch Defective?
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\b NO
\b YES
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\b Replace Blower Motor
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\b * Apply 12V
Directly To YES
Clutch
\b * Is Clutch
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Defective? Is The Switch Defective?
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\b \
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\b
YES YES
\b \b
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Replace Clutch Replace Switch
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\b \
\b
NO NO
\b \b
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Repair Wiring Repair The Wiring Harness
NO Harness \
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\b \b \
\b
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Low R-12 Refrigerant?
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\b \
NO \
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YES Charge System
\b \b \
\b
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Is The Pressure Switch Defective?
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\b
YES \
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NO
\b \b
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Replace Pressure Switch Replace Expansion Valve
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\b \
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\b
CONDITION & POSSIBLE CAUSE
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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.
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System Charge Test
1) To check system refrigerant level, a sight glass has been
incorporated into the receiver-to-evaporator hose at the receiver end.
A continuous stream of bubbles will appear in the sight glass of a
system that is not properly charged. However, both properly charged
systems and discharged systems will appear the same because of a lack
of bubbles.
2) To test for discharge condition, cycle the clutch off and
on with engine at 1500 RPM. When clutch is off, bubbles will appear if
there is refrigerant in the system. If no bubbles appear, system is
discharged. If discharged, leak test, repair and recharge system.
A/C SYSTEM OPERATION CHART & VACUUM DIAGRAM
A/C SYSTEM OPERATION TABLE \
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MODE
LEVER BLOWER PANEL FLOOR DEFROST WATER
POSITION AIR DISCHARGE SPEEDS DOOR DOOR DOOR VALVE
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\f\
\f\
\f\
\f\
\f\
\f\
Off(
1)( 2) Closed None Open ( 3) Closed Closed
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\f\
\f\
\f\
\f\
\f\
\f\
Max A/C Panel Regis- 4
(
1)( 4) ters With Open Bleed Closed Open( 5)
Floor Bleed
\
\f\
\f\
\f\
\f\
\f\
\f\
Norm A/C Panel Regis- 4(
6) Open Bleed Closed Open( 5)
(
7)( 4) ters With
Floor Bleed
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\f\
\f\
\f\
\f\
\f\
\f\
Bi-Level Panel 4(
6) Open Open Bleed Open( 1)
(
7)( 4) Registers
and Floor
With Def.
Bleed
\
\f\
\f\
\f\
\f\
\f\
\f\
Vent Panel 4 Open Bleed Closed Closed
(
7)( 2) Registers
With Floor
Bleed
\
\f\
\f\
\f\
\f\
\f\
\f\
Heat Floor With 4 Closed Open Bleed Open(
1)
(
7)( 2) Def. Bleed
\
\f\
\f\
\f\
\f\
\f\
\f\
Def. Defroster 4 Closed Bleed Open Open(
1)
(
7)( 2) With Floor
Bleed
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(
1) - Recirculating Door is in Recirc. position.
(
2) - Indeterminate
(
3) - A/C Compressor is OFF
(
4) - A/C Compressor is ON
(
5) - Water valve closes in full "COOL" temperature lever position.
(
6) - Speeds are reduced by approximately 2.0 Volts.
(
7) - Recirculating Door is in Outside position.
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\b
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Fig. 7: A/C Control System Vacuum Diagram
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\003
* 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
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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
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are continually republished. In addition to these, standards for Drive
Train and Transmissions have recently been promulgated. Participating
shops utilize these Uniform Inspection & Communication Standards as
part of the inspection process and for communicating their findings to
their customers.
The Motorist Assurance Program continues to work
cooperatively and proactively with government agencies and consumer
groups toward solutions that both benefit the customer and are
mutually acceptable to both regulators and industry. We maintain the
belief that industry must retain control over how we conduct our
business, and we must be viewed as part of the solution and not part
of the problem. Meetings with state and other government officials
(and their representatives), concerned with auto repair and/or
consumer protection, are conducted. Feedback from these sessions is
brought back to the association, and the program adjusted as needed.
To assure auto repair customers recourse if they were not
satisfied with a repair transaction, the Motorist Assurance Program
offers mediation and arbitration through MAP/BBB-CARE and other non-
profit organizations. MAP conducted pilot programs in twelve states
before announcing the program nationally in October, 1998. During the
pilots, participating repair shops demonstrated their adherence to the
Pledge and Standards and agreed to follow the UICS in communicating
the results of their inspection to their customers. To put some
"teeth" in the program, an accreditation requirement for shops was
initiated. The requirements are stringent, and a self-policing method
has been incorporated which includes the "mystery shopping" of
outlets.
We welcome you to join us as we continue our outreach... with
your support, both the automotive repair industry and your customers
will reap the benefits. Please visit MAP at our Internet site www.
motorist.org or contact us at:
1444 I Street, NW Suite 700
Washington, DC 20005
Phone (202) 712-9042 Fax (202) 216-9646
January 1999
MAP UNIFORM INSPECTION GENERAL GUIDELINES
OVERVIEW OF SERVICE REQUIREMENTS & SUGGESTIONS
It is MAP policy that all exhaust, brake, steering,
suspension, wheel alignment, drive-line, engine performance and
maintenance, and heating, ventilation and air conditioning, and
electrical services be offered and performed under the standards and
procedures specified in these sections.
Before any service is performed on a vehicle, an inspection
of the appropriate system must be performed. The results of this
inspection must be explained to the customer and documented on an
inspection form. The condition of the vehicle and its components will
indicate what services/part replacements may be "Required" or
"Suggested". In addition, suggestions may be made to satisfy the
requests expressed by the customer.
When a component is suggested or required to be repaired or
replaced, the decision to repair or replace must be made in the
customer's best interest, and at his or her choice given the options
available.
This section lists the various parts and conditions that
indicate a required or suggested service or part replacement.
Although this list is extensive, it is not fully inclusive. In
addition to this list, a technician may make a suggestion. However,
any suggestions must be based on substantial and informed experience,
Page 120 of 1378
or the vehicle manufacturer's recommended service interval and must be
documented.
Some conditions indicate that service or part replacement is
required because the part in question is no longer providing the
function for which it is intended, does not meet a vehicle
manufacturer's design specification or is missing.
Example:
An exhaust pipe has corroded severely and has a hole in it
through which exhaust gases are leaking. Replacement of the
exhaust pipe in this case is required due to functional
failure.
Example:
A brake rotor has been worn to the point where it measures
less than the vehicle manufacturer's discard specifications.
Replacement of the rotor is required because it does not meet
design specifications.
Some conditions indicate that a service or part replacement
is suggested because the part is close to the end of its useful life
or addresses a customer's need, convenience or request. If a
customer's vehicle has one of these conditions, the procedure may be
only to suggest service.
Example:
An exhaust pipe is rusted, corroded or weak, but no leaks are
present. In this case, the exhaust pipe has not failed.
However, there is evidence that the pipe may need replacement
in the near future. Replacement of the pipe may be suggested
for the customer's convenience in avoiding a future problem.
Example:
The customer desires improved ride and/or handling, but the
vehicle's shocks or struts have not failed. In this case,
replacement may be suggested to satisfy the customer's
wishes. In this case, replacement of the shocks or struts may
not be sold as a requirement.
A customer, of course, has the choice of whether or not a
shop will service his or her vehicle. He or she may decide not to
follow some of your suggestions. When a repair is required, a MAP shop
must refuse partial service on that system if, in the judgment of the
service provider, proceeding with the work could create or continue an
unsafe condition. When a procedure states that required or suggested
repair or replacement is recommended, the customer must be informed of
the generally acceptable repair/replacement options whether or not
performed by the shop.
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.
The following reasons may be used for required and suggested
services. These codes are shown in the "Code" column of the MAP
Uniform Inspection & Communications Standards that follow:
Reasons to Require Repair or Replacement
A - Part no longer performs intended purpose
B - Part does not meet a design specification (regardless of
performance)
C - Part is missing
NOTE: When a repair is required, the shop must refuse partial