35S05T0 advanced climate control diagnosis 2006

PREREQUISITE REVIEWA/C Clutch Cycling Control The A/C cycling switch interrupts compressor operation, via the PCM and A/C clutch relay, beforethe external temperature of the A/C evaporat

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Ford Customer Service Division Technical Training

student guide

FCS-14571-REFigk igk

Updated January, 2006

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Appropriate service methods and proper repair procedures are essential for the safe, reliable operation of all motor vehicles,

as well as the personal safety of the individual doing the work This manual provides general directions for accomplishing service and repair work with tested, effective techniques Following them will help assure reliability.

There are numerous variations in procedures, techniques, tools and parts for servicing vehicles, as well as in the skill of the individual doing the work This manual cannot possibly anticipate all such variations and provide advice or cautions as to each Accordingly, anyone who departs from instructions provided in this manual must first establish that he compromises neither his personal safety nor the vehicle integrity by his choice of methods, tools or parts.

As you read through the procedures, you will come across NOTES, CAUTIONS, and WARNINGS Each one is there for a specific purpose NOTES give you added information that will help you to complete a particular procedure CAUTIONS are given to prevent you from making an error that could damage the vehicle WARNINGS remind you to be especially careful

in those areas where carelessness can cause personal injury The following list contains some general WARNINGS that you should follow when you work on a vehicle.

• Always wear safety glasses for eye protection.

• Use safety stands whenever a procedure requires you to

be under the vehicle.

• Be sure that the ignition switch is always in the OFF

position, unless otherwise required by the procedure.

• Set the parking brake when working on the vehicle If you

have an automatic transmission, set it in PARK unless

instructed otherwise for a specific service operation If

you have a manual transmission it should be in

RE-VERSE (engine OFF) or NEUTRAL (engine ON) unless

instructed otherwise for a specific service operation.

• Operate the engine only in a well-ventilated area to avoid

the danger of carbon monoxide.

• Keep yourself and your clothing away from moving parts

when the engine is running, especially the fan and belts.

• To prevent serious burns, avoid contact with hot metal parts such as the radiator, exhaust manifold, tail pipe, catalytic converter and muffler.

• Do not smoke while working on the vehicle.

• To avoid injury, always remove rings, watches, loose hanging jewelry, and loose clothing before beginning to work on a vehicle Tie long hair securely behind your head.

• Keep hands and other objects clear of the radiator fan blades Electric cooling fans can start to operate at any time by an increase in underhood temperatures, even though the ignition is in the OFF position Therefore, care should be taken to ensure that the electric cooling fan is completely disconnected when working under the hood.

The recommendations and suggestions contained in this manual are made to assist the dealer in improving his dealership parts and/or service department operations These recommendations and suggestions do not supersede or override the provisions of the Warranty and Policy Manual, and in any cases where there may be a conflict, the provisions of the Warranty and Policy Manual shall govern.

The descriptions, testing procedures, and specifications in this handbook were in effect at the time the handbook was approved for printing Ford Motor Company reserves the right to discontinue models at any time, or change specifications, design, or testing procedures without notice and without incurring obligation Any reference to brand names in this manual

is intended merely as an example of the types of tools, lubricants, materials, etc recommended for use Equivalents, if available, may be used The right is reserved to make changes at any time without notice.

WARNING: Many brake linings contain asbestos fibers When working on brake components, avoid breathing the dust Breathing

the asbestos dust can cause asbestosis and cancer.

Breathing asbestos dust is harmful to your health.

Dust and dirt present on car wheel brake and clutch assemblies may contain asbestos fibers that are hazardous to your health when made airborne by cleaning with compressed air or by dry brushing.

Wheel brake assemblies and clutch facings should be cleaned using a vacuum cleaner recommended for use with asbestos fibers Dust and dirt should be disposed of in a manner that prevents dust exposure, such as sealed bags The bag must be labeled per OSHA instructions and the trash hauler notified as to the contents of the bag.

If a vacuum bag suitable for asbestos is not available, cleaning should be done wet If dust generation is still possible, technicians should wear government approved toxic dust purifying respirators.

OSHA requires areas where asbestos dust generation is possible to be isolated and posted with warning signs Only technicians concerned with performing brake or clutch service should be present in the area.

Technical Support Operations Ford Customer Service Division March, 2005

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SERVICE STANDARDS Mission Statement:

All dealership personnel will treat every customer as a potential lifetime purchaser, communicating a professional image which embraces honesty and concern for customer wants and needs.

4. Vehicles serviced right on the first visit.

5. Service status provided within one minute

of inquiry

6. Vehicle ready at agreed upon time

7. Thorough explanation of work done,coverages and changes

1. Appointment available within one day of

the customer’s requested service day

2. Write-up begins within four minutes of

arrival

3. Service needs courteously identified,

accurately recorded on Repair Order,

and verified with customer

These seven service standards provide a process and product value that are compellingreasons for owners to purchase and repurchase Ford or Lincoln-Mercury products Thesestandards also help to attract new owners through favorable testimonials and improved ownersatisfaction

Standard 4

“Fix It Right the First Time, on Time.”

The technician is the most important player when it comes to Standard #4.

Why

Customers tell us “Fixing It Right the First Time, on Time” is one of the reasons they woulddecide to return to a dealer to buy a vehicle and get their vehicles serviced

Technician Training

It is our goal to help the technician acquire all of the skills and knowledge necessary to

“Fix it Right the First Time, on Time.” We refer to this as “competency.”

Technician’s Role

Acquire the skills and knowledge for competency in your specialty via

— Ford Multimedia Training (FMT) — Instructor-Led

— Instructor-Led

The Benefits

The successful implementation of standards means

— Satisfied customers

— Repeat vehicle sales

— Repeat service sales

— Recognition that Ford and Lincoln/Mercury technicians are

Dealer-to-Customer Service Standards:

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INTRODUCTION

Advanced Climate Control Diagnosis and Service (Instructor-Led) Intro - 2 Course Description Intro - 3 Course Objective Intro - 3 Course Requirements Intro - 3 Worksheets Intro - 3

PREREQUISITE REVIEW

Cycling Clutch Orifice Tube System Operation (CCOT) Prereq - 4 Thermostatic Expansion Valve A/C system (TXV) Prereq - 10 PCM Strategies Prereq - 14 Activity A Prereq - 18 Activity B Prereq - 19 Activity C Prereq - 20 Auxiliary Climate Control System Prereq - 22 Demonstration Prereq - 25

DAY ONE

Workstation One 1 - 2 Workstation Two 1 - 4 Workstation Three 1 - 8 Workstation Four 1 - 14

DAY TWO

Activity A 2 - 2 Automatic Temperature Control 2 - 4 SSCC diagnostic process 2 - 6 Electronic Automatic Temperature Control Module Self-Test 2 - 7 Dual Automatic Temperature Control Module Self-Test 2 - 8 Vacuum chart diagnostic process 2 - 10

Workstation One 2 - 20 Workstation Two 2 - 22 Workstation Three 2 - 24 Workstation Four 2 - 26

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ROTUNDA ORDER FORM Rotunda - 1

Climate Controlled Seat System 3 - 2 Workstation One 3 - 6 Workstation Two 3 - 7 Workstation Three 3 - 8 Workstation Four 3 - 12 Tool List 3 - 16

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Advanced Climate Control System Diagnosis March, 2005 INTRO - 1

INTRODUCTION

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CLIMATE CONTROL CURRICULUM

Planned Training Pathway

Electrical/Electronics Curriculum

Climate Control Theory and Operation (Web-Based)

Electronic Climate Control Systems – Operation and Diagnosis (Web-Based)

Advanced Climate Control Diagnosis and Service (Instructor-Led)

Ford Motor Company has identified the skills and knowledge necessary to meet the curriculum goals

in the Climate Control Specialty The Planned Training Pathway is a series of courses designed toprovide you with these skills and knowledge The chart above illustrates the courses in this

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Advanced Climate Control System Diagnosis March, 2005 INTRO - 3

Advanced Climate Control Diagnosis and Service (Instructor-Led)

Course Description

This is a three-day hands-on course The course is designed to provide you with maximum practiceand application of diagnostic and service skills The first day, you will practice these skills on fourdifferent worksheets The second day, you will continue to practice these skills on four more

worksheets The third day, you will receive four more opportunities to practice Before the end of thecourse, you will have had 12 opportunities to practice your diagnostic and service skills The results

of your work will be recorded on worksheets

Worksheets

All hands-on activities will be guided by worksheets When you are assigned to a workstation, youwill be given 30 to 45 minutes to complete the worksheet Every 30 to 45 minutes, you will move tothe next workstation and complete another worksheet

Course Requirements

To meet the requirements of this course, you must satisfactorily complete a post-test that will be

administered on the afternoon of the third day The post-test includes a combination of hands-on andwritten exercises A score of 80% or higher is required to pass the 30 question written test

Course Objectives

The purpose and the objectives of this course are to enable you to:

• Retrieve DTCs from the control head and Powertrain Control Module

• Diagnose refrigeration, heating, air management and control subsystem concerns

• Diagnose powertrain control concerns related to the compressor clutch and electric engine coolingfan circuit(s)

• Use special service tools and diagnostic and service equipment related to the refrigeration, heatingand control subsystems

• Perform service procedures related to the refrigeration, heating, air management and control

subsystems

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Prereq - 1 March, 2005

Advanced Climate Control System Diagnosis

PREREQUISITE

REVIEW

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DIRECTIONS: Answer the following heating system questions.

1 Which component of the heater system allows the heater core to effectively transfer heat?

A Heater hoses

B Blower motor

C Water valve

D Engine cooling fan

2 Which of the following symptoms would lead you to perform a heater core pressure test?

A Engine coolant leaking into the passenger compartment

B Engine coolant causing fogging on the windshield

C The smell of engine coolant inside the passenger compartment

D Any of these symptoms

3 Which component keeps hot coolant out of the heater core during A/C operation?

A Blower motor

B Blend door actuator

C Coolant shut off valve

D Water pump

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A/C Clutch Cycling Control

The A/C cycling switch interrupts compressor operation, via the PCM and A/C clutch relay, beforethe external temperature of the A/C evaporator core gets low enough to cause the condensed watervapor (excess humidity) to turn to ice It does this by monitoring low side line pressure and sends asignal to the PCM The PCM cycles the A/C clutch relay to control the A/C clutch based on the A/Ccycling switch input It is known that a refrigerant pressure of approximately 210 kPa (30 psi) willyield an operating temperature of 0°C (32°F) The A/C cycling switch controls system operation in

an effort to maintain this temperature

The high side line pressure is also monitored so that A/C compressor operation can be interrupted ifsystem pressure becomes too high

The A/C compressor relief valve will open and vent refrigerant to relieve unusually high systempressure

The cycling clutch orifice tube type system consists of a compressor, condenser core, evaporatorcore orifice, evaporator core, suction accumulator, refrigerant lines, control sensors, and switches

Operation

During stabilized conditions (A/C off), the refrigerant pressures are equal throughout the system.When the A/C compressor is in operation it increases pressure on the refrigerant vapor, raising itstemperature The high-pressure and high-temperature vapor is then released into the top of the A/Ccondenser core

The A/C condenser core causes the refrigerant vapor to condense into a liquid when heat is removedfrom the refrigerant by ambient air passing over the fins and tubing The now liquid refrigerant, still

at high pressure, exits from the bottom of the A/C condenser core and enters the inlet side of the A/Cevaporator core orifice

The A/C evaporator core orifice is the restriction in the refrigerant system that creates the highpressure buildup upstream of the A/C condenser core and separates the high and low pressure sides

of the A/C system As the liquid refrigerant leaves this restriction, its pressure and boiling point arereduced

The liquid refrigerant is now at its lowest pressure and temperature As it passes through the A/Cevaporator core, its absorbs heat from the airflow passing over the plate/fin sections of the A/Cevaporator core This addition of heat causes the liquid refrigerant to boil (convert to vapor) Thenow cooler air can no longer support the same humidity level of the warmer air, and this excessmoisture condenses on the exterior of the evaporator coils and fins and drains outside the vehicle.The suction accumulator/drier is designed to remove moisture from the refrigerant and to preventany liquid refrigerant that may not have been vaporized in the evaporator core from reaching the A/Ccompressor The A/C compressor is designed to pump refrigerant vapor only, as liquid refrigerantwill not compress and can damage the A/C compressor

Cycling Clutch Orifice Tube System Operation (CCOT)

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4 In the art above identify the A/C system components by filling in the name of the component on the blank lines provided

5 What is the purpose of the A/C cycling switch?

CCOT A/C System

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PREREQUISITE REVIEWBasic Clutch Control

ACCR - Air Conditioning Clutch Relay

WAC - WOT A/C Clutch Command

WOT - Wide Open Throttle

PID Definition

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PREREQUISITE REVIEWPCM Clutch Control - Cycling Switch

ACCS - Air Conditioning Cycling Switch

Note: Pressures are approximate

PID Definition

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Evaporator Temperature Sensor

The PCM determines A/C compressor clutch cycling based on input from the evaporator dischargeair temperature sensor

The evaporator air discharge temperature sensor:

• is located in the evaporator core housing just downstream of the evaporator airflow

• contains a thermistor, which receives a reference voltage from the PCM The thermistor then variesthe resistance to the reference voltage based on the evaporator discharge air temperature The PCMinterprets the voltage as an evaporator air discharge temperature reading

The PCM maintains evaporator core temperature, and prevents icing of the evaporator core bydisengaging the A/C compressor clutch when the evaporator discharge air temperature falls below apreset level, and engaging the A/C compressor clutch when the discharge air temperature rises above

a preset level

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PREREQUISITE REVIEWPCM Clutch Control - Evaporator Temp Sensor

ACET - Air Conditioning Evaporator Temperature

A/C T - Air Conditioning Evaporator Temperature

A/CTV - Air Conditioning Evaporator Temperature Voltage

PID Definition

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Refrigerant Cycle

During stabilized conditions (air conditioning system shutdown), the refrigerant pressures are equalthroughout the system When the A/C compressor is in operation, it increases pressure on the refrig-erant vapor raising its temperature The high-pressure, high-temperature vapor is then released intothe top of the A/C condenser core

The A/C condenser core, being close to ambient temperature, causes the refrigerant vapor to dense into a liquid when heat is removed from the refrigerant by ambient air passing over the finsand tubing The now liquid refrigerant, still at high pressure, exits from the bottom of the A/C con-denser core and enters the inlet side of the receiver/drier

con-The receiver/drier is designed to remove moisture from the refrigerant con-The refrigerant, still at highpressure, exits the receiver/drier and enters the thermostatic expansion valve

The thermostatic expansion valve is the restriction in the refrigerant system that creates the pressure buildup in the A/C condenser core and separates the high and low-pressure sides of the A/Csystem As the liquid refrigerant leaves this restriction, its pressure and boiling point are reduced.The liquid refrigerant is now at its lowest pressure and temperature As it passes through the A/Cevaporator core, it absorbs heat from the airflow passing over the plate/fin sections of the A/C

high-evaporator core This addition of heat causes the liquid refrigerant to boil (convert to vapor) Thenow cooler air can no longer support the same humidity level of the warmer air and this excessmoisture condenses on the exterior of the evaporator coils and fins and drains outside the vehicle.The refrigerant cycle is now repeated with the A/C compressor again increasing the pressure andtemperature of the refrigerant

A/C Clutch Cycling Control

The A/C thermostatic cycling switch interrupts compressor operation before the external temperature

of the A/C evaporator core gets low enough to cause the condensed water vapor (excess humidity) toturn to ice It does this by supplying an ON/OFF command to the PCM

The low charge protection switch protects the A/C compressor in the event of a low refrigerantcharge The low charge protection switch interrupts the voltage to the A/C thermostatic cyclingswitch when the low side refrigerant pressure drops below acceptable levels

The high side line pressure is also monitored so that A/C compressor operation can be interrupted ifsystem pressure becomes too high

The A/C compressor relief valve will open and vent refrigerant to relieve unusually high systempressure

Thermostatic Expansion Valve A/C system (TXV)

The thermostatic expansion valve system consists of a compressor, condenser core, receiver/drier,thermostatic expansion valve, evaporator core, refrigerant lines, control sensors, and switches

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PREREQUISITE REVIEW Thermostatic Expansion Valve A/C system

6 In the art above identify the thermostatic expansion valve A/C system components by filling in

the name of the component on the blank lines provided

7 In a thermostatic expansion valve A/C system, which component retains any vapor that leaves thecondenser until it becomes a liquid?

A Suction Accumulator/Drier

B Receiver/Drier

C Thermostatic Expansion Valve

D Fixed Orifice Tube

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PREREQUISITE REVIEWPCM Clutch Control - TXV Switch

PID Definition

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PCM Strategies

The purpose of the PCM is to ensure efficient engine operation Since the PCM must accomplish thispurpose under many different conditions, it has many different operating strategies Some of theoperating strategies call for disengaging the compressor clutch Other strategies concern enginecooling fan operation Therefore, it is important to understand which inputs to the PCM may causerefrigeration system concerns

Compressor Anti-Slugging Strategy (CASS)

Liquid refrigerant may accumulate in the A/C compressor under certain conditions To alleviatedamage to the A/C compressor, compressor anti-slugging strategy (CASS) is utilized on some

vehicles

CASS is initiated only under specific conditions:

• the ignition is off for more than 8 hours

• the ambient temperature is above -4°C (25°F)

• battery voltage is above 8.5 volts during engine cranking

When these conditions are present, the powertrain control module (PCM) will activate the A/Ccontrol relay prior to cranking of the engine The A/C control relay engages the A/C compressor forapproximately 4 to 15 A/C compressor revolutions or a maximum of two seconds (depending onvehicle application), allowing the liquid refrigerant to be pushed from the A/C compressor CASS isinitiated by the PCM regardless of the function selector switch position

Engine Load and Compressor Clutch Engagement

The A/C compressor takes engine horsepower to operate When the compressor clutch is engagedthe engine RPM slows down The PCM recognizes the fact that the engine must makeup for the losthorsepower Therefore, the PCM compensates the engine RPM to maintain engine speed

Wide Open A/C Cut-Out Strategy (WAC)

During certain operating conditions the PCM may engage the Wide Open A/C Cut-Out Strategy(WAC) to disengage the A/C clutch

The following conditions may initiate the WAC strategy:

• High power steering pressures during parking maneuvers

• Wide Open Throttle strategy (WOT) operation

• If the engine temperature reaches approximately 245 degrees F (118 degrees C)

• If high side refrigerant pressures become excessive

• If the PCM dectects a fault in other systems

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PREREQUISITE REVIEWPCM Strategies (continued)

Cooling Fan

When a vehicle is first started the cooling fan is usually off in order to bring the engine up to ing temperature as soon as possible As the engine temperature continues to rise, as indicated to thePCM by the ECT sensor, the PCM switches the LFC relay With the LFC closed the engine coolingfan begins to operate at low speed (On vehicles with two fans, the primary fan would begin to

operat-operate.) The PCM will then monitor engine load, performance and coolant temperature If the PCMdetermines that the engine load or operating temperatures are excessive, the HFC may be switched

on When the PCM switches on the HFC, the engine cooling fan will operate at high speed (On

vehicles with two fans, the secondary fan would begin to operate.)

When the vehicle is operating at a steady cruise the PCM may open the HFC or LFC relays in order

to reduce fan speed or to turn off the fan The reason for this is that normal air flow through the

radiator/condenser area may be sufficient for heat transfer The PCM will make the decision to openthe relay(s) based on the VSS, TP sensor, ECT sensor, engine load and whether or not the compres-sor clutch is engaged

Hot Engine Strategy

More than likely if the engine is overheating, it will be in the dealership for a drivability concern

However, if the engine temperature reaches approximately 245 degrees F (118 degrees C) the PCMwill engage the WAC strategy The ECT/CHT sensor is the input for this strategy

Fail-Safe Cooling Strategy

The fail-safe cooling strategy is activated by the PCM only in the event that an overheating

condition has been identified This strategy provides engine temperature control when the cylinder

head temperature exceeds certain limits The cylinder head temperature is measured by the cylinderhead temperature (CHT) sensor Note: Not all vehicles equipped with a CHT sensor will have the

fail-safe cooling strategy

A cooling system failure such as low coolant or coolant loss could cause an overheating condition

As a result, damage to major engine components could occur Along with a CHT sensor, the fail-safecooling strategy is used to prevent damage by allowing air cooling of the engine This strategy

allows the vehicle to be driven safely for a short time with some loss of performance when an

overheat condition exists

Engine temperature is controlled by varying and alternating the number of disabled fuel injectors

This allows all cylinders to cool When the fuel injectors are disabled, their respective cylinders

work as air pumps, and this air is used to cool the cylinders The more fuel injectors that are

disabled, the cooler the engine runs, but the engine has less power

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PREREQUISITE REVIEWPCM Clutch Control - with Cooling Fan

ACPSW - Air Conditioning Pressure Switch

LFC - Low Speed Fan Control

HFC - High Speed Fan Control

PID Definition

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PREREQUISITE REVIEWPCM Clutch Control - with Variable Fan

ACET - Air Conditioning Evaporator Temperature

A/C T - Air Conditioning Evaporator Temperature

A/CTV- Air Conditioning Evaporator Temperature Voltage

ACP - Air Conditioning Pressure Sensor

ACPV - Air Conditioning Pressure Sensor Voltage

FANVAR - Fan Control Variable Speed

FAN_CTRL - Fan Speed Control

PID Definition

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ACTIVITY A

END OF ACTIVITY

DIRECTIONS: Go to the classroom vehicle Locate the climate control system components

that perform the functions listed in the right hand column List the name of the components

that match the letter on the tag attached to each component in the left column

VEHICLE:

Improves A/C efficiency by keeping hot coolant out

of the heater core during A/C operation

Protects the system from excessive high side systempressure that may cause A/C component damage

Measures the temperature of outside air and sendsthat reading to the electronic control module

Collects liquid refrigerant from the condenser andholds it in reserve until the heat load demandsgreater refrigerant flow

Controls refrigerant flow using a ball and plate bly that is moved by pressure differentials in responce

assem-to temperature

Supplies heated coolant to the auxiliary heater core

Protects the A/C compressor in the event of a lowcharge

Returns refrigerant from the auxiliary evaporator core

to the compressor

TAG COMPONENT NAME COMPONENT FUNCTION

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Prereq - 19 January, 2006

ACTIVITY B

DIRECTIONS: Go to the classroom vehicle Locate the climate control system components

that perform the functions listed in the right hand column List the name of the components

that match the letter on the tag attached to each component in the left column

propor-Contains a photovoltaic diode that is sensitive tosunlight

TAG COMPONENT NAME COMPONENT FUNCTION

END OF ACTIVITY

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ACTIVITY C

DIRECTIONS: Using the service publications, student guide and your knowledge, answer

the following questions

Circle the appropriate choice:

1 The refrigerant line between the A/C compressor and the condenser contains a (low) (high) sure (vapor) (liquid) and feels (hot) (warm) (cold) to touch on a normally operating system

pres-2 The refrigerant line between the condenser and the orifice tube contains a (low) (high) pressure(vapor) (liquid) and feels (hot) (warm) (cold) to touch on a normally operating system

3 The refrigerant line between the orifice tube and the evaporator contains a (low) (high) pressure(vapor) (liquid) and feels (hot) (warm) (cold) to touch on a normally operating system

4 The refrigerant line between the evaporator and the A/C compressor contains a (low) (high)pressure (vapor) (liquid) and feels (hot) (warm) (cold) to touch on a normally operating system

5 Which inputs are used to control the A/C clutch on a 2005 Explorer with manual A/C?

A/C Clutch Cycling Switch A/C Evaporator Air Temp Sensor

A/C High Pressure Cut-Off Switch Low Charge Protection Switch

Dual A/C Pressure Switch A/C Pressure Transducer

6 Describe how the inputs you chose in question 5 control A/C clutch operation

Continued on the next page

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ACTIVITY C

7 Which inputs are used to control the A/C clutch on a 2005 Grand Marquis with manual A/C ?

A/C Clutch Cycling Switch A/C Evaporator Air Temp Sensor

8 Describe how the inputs you chose in question 7 control A/C clutch operation

9 In addition to the Thermostatic Expansion Valve (TXV) that has an integral thermostatic switch

and low charge protection switch, which inputs are used to control the A/C clutch on a 2004 tion?

Expedi-A/C Clutch Cycling Switch A/C Evaporator Air Temp Sensor

10 Describe the operation of the Thermostatic Expansion Valve (TXV)

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PREREQUISITE REVIEWAUXILIARY CLIMATE CONTROL SYSTEM

In a front and rear climate control system the driver can control both the front and the rear (or iary system) from the front of the vehicle or allow the rear passengers to control the rear system Inorder to learn how the front and rear system operates we will use a typical system as our examplevehicle However, operation of front and rear systems may vary greatly from vehicle to vehicle.The typical system uses two refrigeration systems combined into one in order to provide cooling toboth the front and the rear of the vehicle A fixed orifice tube refrigeration subsystem is used to coolthe front A thermostatic expansion valve is used to control refrigerant flow to the rear However, therear refrigeration system is not a complete system It only contains a thermostatic expansion valveand an evaporator that are connected to the front fixed orifice tube system The front system suppliesthe compressor, suction accumulator/drier and the condenser for both systems In addition, thissystem uses some heater core coolant shutoff valves to shut off front or rear coolant flow to theheater cores

auxil-Some of the features of the typical front and rear system include:

• a temperature blend control knob on the rear control head

• the ability to control the discharge air location from the rear control head

• dual heater core coolant shutoff valves that shut off engine coolant to the heater cores during A/Coperation

The control operations for the front and rear system will be divided according to the purposes of thecontrol subsystem

Both the front and rear control assemblies use push buttons that are connected to electric actuators tocontrol the air distribution doors The front air management system contains four distribution doorsthat are used to obtain the following six air flow possibilities:

• UPPER PANEL VENT

• LOWER PANEL VENT

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PREREQUISITE REVIEWAUXILIARY CLIMATE CONTROL SYSTEM

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DEMONSTRATION

Sealant Detector

Refrigerant system reclaim and evacuation

How long should the system evacuation take?

What state should the engine be in, during sealant detection?

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NOTES

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Advanced Climate Control System Diagnosis March, 2005 1 - 1

DAY ONE WORKSTATIONS

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WORKSTATION 1 ANALYZE REFRIGERANT AND MONITOR SYSTEM OPERATION

VEHICLE:

DIRECTIONS: Answer the following questions.

1 Where can you find information for the type of refrigerant that should be in the refrigeration tem?

4 Use the Quick Detect tool to test for A/C sealant by following steps 1 - 11 in the instructions While

performing step # 8, what was the flow rate?

5 What could happen if sealant has been installed into a system?

Refer to section 412-00 General Procedures of the workshop manual to answer question # 8

8 What should you do if the refrigerant analyzer indicates that the wrong refrigerant is in the system?

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Advanced Climate Control System Diagnosis March, 2005 1 - 3

WORKSTATION 1 ANALYZE REFRIGERANT AND MONITOR SYSTEM OPERATION

Using the tables below monitor the A/C pressure gauges at idle Use the Workshop Manual

proce-dure (412-00, General Proceproce-dures, Refrigerant System Test) to prepare the vehicle If the clutch

cycles, record the times below

Now monitor the values at approximately 1500 rpm’s

E L B A T C I T S O N G A I D p m e T t n e i b m A

p m e T l e n a P

e g u a G h g i

e g u a G w o

e m i T N O h c t u l C

e m i T F F O h c t u l C

e m i T e l c y C l a t o T

E L B A T C I T S O N G A I D p m e T t n e i b m A

p m e T l e n a P

e g u a G h g i

e g u a G w o

e m i T N O h c t u l C

e m i T F F O h c t u l C

e m i T e l c y C l a t o T

END OF WORKSHEET

e r u t a r e p m e t e v i t a l e r r i e h t e n i m r e t e d o t s e n i t n a r e g i r f e r e h t h c u o

T

p m e T e n i L r o t a r o

n

o

C I n l e : cold /warm/ ot O u t l e : cold /warm/ ot

e r u t a r e p m e t e v i t a l e r r i e h t e n i m r e t e d o t s e n i t n a r e g i r f e r e h t h c u o

T

p m e T e n i L r o t a r o

n

o

C I n l e : cold /warm/ ot O u t l e : cold /warm/ ot

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WORKSTATION 2 (Part 1) A/C CYCLING SWITCH ON VEHICLE

P C o m p r e s o r O N C o m p r e s o r O F

D I P S C C A

D I P R C C A / C A W

3 Unplug the A/C clutch cycling switch and measure ist’s resistance the switch is? (Circle one) Open orClosed

4 Monitor the ACCS and WAC/ACCR PIDs

• Run the engine at 1500 RPM with A/C on.

• Reconnect the A/C clutch cycling switch.

• Access Datalogger with the scan tool.

• Monitor the ACCS and WAC/ACCR PIDs.

• Fill in the table below.

5 With the engine at 1500 RPM, record the following information in the table below

• Wait for the discharge temp to stabilize before making your readings.

• Take pressure readings when the compressor cycles off.

d e S

e i S w o e r u s r P

e i S h i H e r u s r

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