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Ford Falcon. Manual - part 312

412-03-21 Air

Conditioning 412-03-21

DIAGNOSIS AND TESTING (Continued)

Normal Low side Pressure

Air Conditioning System Performance Test Diagnostics

Vent temp

Disch press

Suct press

Clutch on time

Fault

Likely cause

High

Long to

Low condenser air Blocked condenser or

continuous

flow.

radiator core.

One or both cooling

fans not working.

Non approved parts

blocking air flow.

Hot air

Only one cooling fan

recirculating

operating.

through the

Radiator heat shields

condenser.

missing.

High

Normal to high Long to

Air in the system. Poor evacuation.

continuous

High

Normal to high Normal to low

Long to

Low refrigerant to Blocked or wrong size

continuous

the evaporator.

orifice.

High

Normal to high Normal

Long to

Low refrigerant

Leaking joint, pipe, or

continuous

charge.

component.

Normal to

Normal to low

Normal

Long to

Partial blockage

Contamination in

high

continuous

of the evaporator

refrigerant circuit.

refrigerant circuit. Damaged, crimped or

dented evaporator

tubes.

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412-03-22 Air

Conditioning 412-03-22

DIAGNOSIS AND TESTING (Continued)

Vent temp

Disch press

Suct press

Clutch on time

Fault

Likely cause

High

Normal

Long to

Heat pick up in air Fresh/recirc door not

continuous

inlet system.

fully in recirc or

leaking.

Hot engine

compartment air

drawn into the inlet.

Excessive oil in

Failure to flush before

system.

changing compressor.

High

Normal

Heat pick up in

Temp control not

the air delivery

achieving full.

system. (after the

evaporator core)

High

Low

Normal

Long to

Condenser

Damaged or crimped

continuous

refrigerant flow

condenser tube.

low.

Contaminants blocking

refrigerant circuit.

High

Low

High

Long to

Poor compressor

Worn or damaged

continuous

performance.

compressor.

Compressor drive belt

or clutch slipping.

Restricted suction Delaminated, crimped

line.

or block suction line.

Normal to

Normal to low

High

Long to

Insufficient

Wrong orifice tube

high

continuous

restriction at

fitted.

orifice.

Damaged or missing

orifice tube ‘O’ ring.

Normal

High

Normal to high Normal

Refrigerant over

Topping up instead of

charge.

full evac and charge.

Normal

Normal to low

short

Low evaporator

Partially blocked

airflow.

evaporator fins.

Restriction in recirc

duct.

Low

Normal to low

continuous

Clutch not

Evaporator air off

disengaging.

thermistor faulty or not

clipped into the correct

core location

R-134a fluorescent tracer dye has been added to the

A/C System Leak Test

A/C system of this vehicle, supplied in the

Two options are available for detection of joint leaks.

accumulator. The refrigerant dye has a limited life of

~500 hours of air conditioning operation.

1. Refrigerant R-134a Leakage detection

Leak checking can be performed with an ultra-violet

NOTE: For more information, refer to Electronic leak

lamp and viewed through U.V. glasses.

detection in this section.

A/C system pressure must be above 551kPa (80psi)

for this operation, and the A/C system must have run

Refrigerant leakage can be determined by a leak

for ~15 minutes prior to leak testing, to allow the dye

detector. Be sure to remove all oil from the test area

to mix thoroughly.

before using the leak detector, because the oil may

contain refrigerant which would give erroneous

Scan all components, fittings and lines with Rotunda

readings.

ultra-violet 164-R0721 or equivalent.

Check for leakage at the compressor shaft seal, and

Leaks can be pin-pointed by bright yellow-green glow

at all system fittings and lines as detailed in Joint

of the tracer dye.

Locations in this Section.

After the leak is repaired, the traces of dye can be

removed from previously leaking areas by using any

2. Alternative Leak detection (leak tracer dye)

general purpose oil solvent.

NOTE: For more information, refer to Fluorescent Dye

leak detection in this section.

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412-03-23 Air

Conditioning 412-03-23

DIAGNOSIS AND TESTING (Continued)

A/C System Noise Test

All compressor driven air conditioning systems will emit noise. Careful system tuning has been undertaken to

suppress most noise emissions. However, with improvements to cabin quietness, customer complaints for

noise, vibration and harshness may need to be addressed. The following chart and proceeding explanations

help with these issues.

Action

Conditions

Inquire about customer complaint

What kind of noise (tone/loudness).

When noise occurs (first time etc.).

Where is it heard from

What conditions it occurs in

Validate the customer claim

Reproduce conditions that noise occurs in

Detail what, when, where noise occurs

Check air conditioning system

Check system layout.

Check gas pressures

Check belt tension and alignment

Make judgement on type of noise

Use attached notes to judge noise

Detail what and where noise occurs

Find noise source and transmission path

Isolate source to verify

Make repair and judge affect

Remove source (replace, unbolt) if faulty component

Mask noise source if possible

Mask transmission path (insulate)

Explain your findings to customer

Detail your activities

If required, request owner to document when noise complaint occurs

to help investigation

Test Procedure

NOTE: This test is used to identify customer complaints.
Vehicle Conditions

Ensure the system is not over charged with refrigerant by conducting an A/C System Performance Test.
Inspect to confirm that system is assembled correctly. That is, compressor is fastened to bracket, drive

belt is tight, condenser is rubber mounted, A/C pipework is not touching body, retaining clamps are in

correct positions, etc.

1. Reproduce the customer complaint noise. (complaint needs to be clearly identified).
2. Gauge if noise is abnormal (it is important to understand the characteristics of the vehicle in its normal

state, to judge what is abnormal). Seek additional advice if necessary.

3. Detail what and how noise occurs.
4. Find the noise source and verify it’s transmission path by isolating suspect part from the vehicle. That is,

float condenser or A/C piping in space to cut the transmission path, etc. If the noise disappears, this

validates the noise source or transmission path.

5. Identify the best method to remove the source. If not possible, mask the source output or isolate the

transmission path.

6. Explain you investigations to the owner, as they are attuned to a noise, and it may be difficult for them to

accept that the total removal of the noise may not be possible. With noise issues, improvement can often

be made but complete removal cannot always be achieved (eg. if the noise complaint is a characteristic of

the actual car or a normal A/C system operating characteristic) . Detailing your findings will make your

explanation easier.

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412-03-24 Air

Conditioning 412-03-24

DIAGNOSIS AND TESTING (Continued)

A/C Noise Symptom Chart

Condition

Source

Action

Internal wear of compressor -

Lack of lubricating oil. In a system with

Check rattling noise from compressor,

Mechanical ‘rattling’ noise occurs with

a gas leak, the oil has escaped with

using a screwdriver to hear

the refrigerant.

compressor internals. Replace

compressor engagement

Lack of lubricating oil has caused wear

compressor and also fix the system
leak to prevent recurrence. Likewise, if

to the compressor internal surfaces.

you detect a leak in the system,
estimate and add refrigerant oil to A/C
system to ensure future compressor
reliability.

Resonant noise with accessory - With

Cause is due to drive accessory

Check the drive accessories. If

A/C on, a ‘cooing’ or ‘woo’ noise can

resonating at specific engine speed.

accessory can be isolated (press down

be heard inside the car. Vibration of

The vibrations are transmitted to the

with a screwdriver) the noise level will

steering wheel can also occur.

be lowered. Repair method can be to

vehicle body causing the noise.

Because resonant noise is similar to

stop vibrations of the assembly or

compressor pulsation noise, you must

modify transmission route to the

distinguish by different checking

vehicle body.

method.

Compressor discharge pulsation noise

Cause is pressure fluctuation of

To check:

- With A/C on, a rumbling noise is

refrigerant discharged from

– Remove the discharge hose

heard inside the vehicle. Vibration of

compressor vibrating the high pressure

mounting clamp and recheck.

steering can also occur. The noise

piping, and abnormal noise occurs by

– Float the condenser without

level rises if the outside temperature is

attachments and recheck.

resonating with the car.

repair:

high.

– Put rubber bush between pipe

clamps.

– If not fixed, decrease refrigerant to

minimum specified level.

For module configurations that effect the air

Module Configuration

conditioning refrigerant system, refer to:

Special Tool(s)

EEC/PCM..........303-14

WDS Diagnostic System (WDS) HIM..................412-04

ICC..................413-08
BEM.................419-10

WDS Parameter Identifier (PID) chart

Special Tool(s)

The air conditioning refrigerant system does not itself

WDS Workshop Diagnostic

contain any programmable modules, but the operation

System

of the climate control system and the output of some

A/C Sensors rely on a number of programmable

modules. These modules are accessed via the WDS

service tool, and the modules may require

re-configuring as part of the repair procedure. The

WDS is used to select appropriate data for the

The following chart lists all PID’s used by the WDS

vehicle, and each module configuration must be

service tool to access data relevant to the system.

relevant for the specific Climate Control system (eg.

MCC, ACC, single zone, dual zone, etc.) and for the

Acronym

Description

circumstance where the module has been modified or

from ECC/PCM

replaced. If this procedure is not followed, the module

ACPRES

A/C Pressure (PSI)

may not function correctly and may set a number of

(1 PSI = 6.89kPa)

Diagnostic Trouble Codes.

HFC

High Speed Fan On (Engine

Cooling Fan)

LFC

Low Speed Fan On (Engine

Cooling Fan)

RPM

Engine Speed (RPM)

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