Ford Falcon. Manual — part 316

412-03-37 Air

Conditioning 412-03-37

DIAGNOSIS AND TESTING (Continued)

PINPOINT TEST G : A/C CYCLING SWITCH (EVAPORATOR THERMISTOR)

Test Step

Result / Action to Take

G1

SYSTEM ON DEMAND SELF TEST

Start and run engine until normal operating temperature is reached.

Yes

Go to G2 if code B2014 is set.

Ensure vehicle battery voltage is within normal operating range

Go to G3 if code B1947 is set.

(12~14volts) before proceeding with test.

No

Using WDS scan tool, record all DTC’s set in the HIM memory.

System is OK.

Using WDS scan tool, clear all DTC’s set in the HIM memory.

Using WDS scan tool, perform HVAC On Demand Self Test (refer
section 412-04).

Are any DTC codes set?

G2

SENSOR WIRING INSPECTION

Disconnect the 2 way Evaporator sensor connector D from the HIM

Yes

and inspect terminals on the sensor lead assembly for damage or

Replace Evaporator sensor

corrosion.

No

Do the terminals appear damaged?

Go to G3.

G3

SENSOR INSPECTION - RESISTANCE

CHARACTERISTIC

Turn off the Air Conditioner, select face outlet, full cold (not A/C Max),

Yes

(’C’ or ’Low’ for ACC) and operate HVAC blower at full speed to

Go to G4.

stabilise the Evaporator sensor temperature.

No

Disconnect the 2 way Evaporator sensor connector D from the HIM.

Replace Evaporator sensor.

Carefully insert the test probes of a resistance meter in to the REAR
of the Evaporator sensor connector (wire side). Inserting probes in to
front of terminals will damage the sensor assembly and cause
intermittent A/C operation. Compare the sensor resistance value
overpage with a temperature thermometer located in the face outlet.

Is the resistance reading within specification (+/- 5 degC) as per
sensor output table?

G4

MODULE FUNCTION CHECK - EVAPORATOR SENSOR

TEMPERATURE READING

Reconnect the sensor 2 way connector D to the HIM.

Yes

System OK.

Connect WDS Scan Tool.

No

Read the A_CT value (Evaporator sensor temperature) from the HIM.

Go to G5.

Does the value closely match the temperature thermometer
located in the face outlet (+/- 5 degC) as per sensor output table
overpage?

G5

MODULE FUNCTION CHECK - EVAPORATOR SENSOR

SUPPLY VOLTAGE

Check the Evaporator sensor supply voltage with a voltmeter.

Yes

Go to G6

With the Evaporator sensor 2 way connector D inserted in to the HIM,
attach the positive probe to pin 2 (LHS) and the negative probe to pin

No

1 (RHS) of the rear of the Evaporator sensor connector. Refer to

Replace HIM

Evaporative sensor connector diagram for correct pin designations.

Using sensor output table, compare the voltage reading against a
temperature probe located in the face outlet with the HVAC Blower
fan operating at high speed.

Does the voltage value closely match the temperature
thermometer located in the face outlet (+/- 5 degC)?

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412-03-38 Air

Conditioning 412-03-38

DIAGNOSIS AND TESTING (Continued)

Test Step

Result / Action to Take

G6

MODULE OUTPUT CHECK - EVAPORATOR SENSOR

SUPPLY VOLTAGE

Remove evaporator sensor plug from HIM.

Yes

System OK.

Using a voltmeter, attach the probes to the HIM output terminals for

Clear DTC.

the evaporator sensor.

No

Ensure ignition key is ON.

Replace HIM.

Is the voltage reading within 4.5-5.5 Volts?

Evaporator Thermister (Temperature Sensor)

Output

Temperature

Sensor

Sensor Voltage

Degrees

Resistance

(Volts)

(Celsius)

(Ohms)

-30

25.37k

4.16

-25

18.90k

3.94

-20

14.19k

3.68

-15

10.73k

3.39

-10

8.17k

3.08

-5

6.27k

2.76

0

4.85k

2.44

5

3.78k

2.13

10

2.97k

1.84

15

2.35k

1.56

20

1.87k

1.34

25

1.50k

1.14

30

1.21k

0.96

35

0.98k

0.81

40

0.75k

0.68

45

0.66k

0.57

50

0.55k

0.48

55

0.45k

0.41

NOTE: Use this table as a guide only. Minor

variations between actual readings are acceptable.

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412-03-39 Air

Conditioning 412-03-39

GENERAL PROCEDURES

3. Remove the A/C charging valve cap from the

Manifold Gauge Set Connection

high-pressure service charge port located on the

liquid line.

Special Tool(s)

R-134a Manifold Gauge Set

or equivalent

1. Turn both valves on the R-134a Manifold Gauge

Set all the way to the left to close the

low-pressure and high-pressure hoses to the

centre manifold and centre hose.

4. Connect the R-134a manifold gauge set

low-pressure hose with the R-134a low side quick

disconnect to the low-pressure service charge

port.

2. Remove the A/C charging valve cap from the

low-pressure service charge port located on the

suction hose assembly.

5. Connect the R-134a manifold gauge set

high-pressure hose with the R-134a high side

quick disconnect to the high-pressure service

charge port.

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412-03-40 Air

Conditioning 412-03-40

GENERAL PROCEDURES (Continued)

5. If a leak is found, recover the refrigerant and

Electronic Leak Detection

repair the system. For additional information refer

to A/C system discharging and recovery in this

Special Tool(s)

section.

Refrigerant Leak Detector

Fluorescent Dye Leak Detection

or equivalent

Special Tool(s)

120 Watt UV Spot Lamp

or equivalent

R-134a Manifold Gauge Set

or equivalent

CAUTION: Good ventilation is necessary in

the area where electronic A/C leak testing is to be

carried out. If the surrounding air is contaminated

with refrigerant gas, the leak detector will indicate

this gas all the time. Odours from other chemicals

such as antifreeze, diesel fuel, disc brake cleaner,

or other cleaning solvents can cause the same

NOTE: Ford Motor Company vehicles are produced

problem. A fan, even in a well-ventilated area, is

with R-134a Leak Tracer Dye incorporated into the

very helpful in removing small traces of

A/C system. The location of leaks can be pinpointed

contamination from the air that might affect the

by the bright yellow-green glow of the tracer dye.

leak detector.

Since more than one leak can exist, always inspect

each component.

1. Be sure to remove all oil from the test area before

using the leak detector, because the oil may

If accumulator is replaced, it is supplied with new dye,

contain refrigerant which would give erroneous

which has a limited life of ~500 hours of Air

readings.

conditioning operation.

2. Remove the Interior Command Centre (ICC).

1. Run the A/C system for ~15 minutes prior to leak

Refer to section 413-08.

testing, to allow the dye to mix thouroughly.

3. Detect for leaks inside the HVAC Case assembly

2. Ensure that the A/C system pressure is between

by inserting the leak detector probe down the vent

413 - 551kPa (60 - 80psi) at 24

°C (75°F) with the

opening in the top of the HVAC case.

engine off.

4. Check for leakage at the compressor shaft seal,

3. Check for leaks using a 120-watt UV spot lamp,

and at all system fittings and lines as per Joint

and viewed through U.V. glasses.

Locations in this section.

4. Observe for die trace at the drain tube of the

Leak test the refrigerant system using the

HVAC above the transmission.

refrigerant leak detector. Follow instructions

5. Scan all components, fittings and lines of the A/C

included with leak detector for handling and

system, as per joint locations listed in Electronic

operation techniques.

Leak Detection in this section.

NOTE: System pressure should be between 413 -

6. Remove the ICC (Refer to section 413-08) and

551kPa (60 - 80psi) at 24

°C (75°F) with the

observe die trace inside the HVAC case

engine off.

assembly.

7. After the leak is repaired, remove any traces of

leak dye with a general purpose oil solvent.

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