heating DAEWOO LACETTI 2004 Service Manual PDF

7B – 8IMANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
DIAGNOSIS
GENERAL DIAGNOSIS
TESTING THE REFRIGERANT
SYSTEM
If you suspect a problem in the refrigerant system, check
for the following conditions:
1. Check the outer surfaces of the radiator and the
condenser cores to be sure that the airflow is not
blocked by dirt, leaves, or other foreign material.
Check between the condenser and the radiator, as
well as all outer surfaces.
2. Check for restrictions or kinks in the condenser
core, the hoses, and the tubes.
3. Check the operation of the blower fan.
4. Check all the air ducts for leaks or restrictions. Low
airflow rate may indicate a restricted evaporator
core.
5. Check for slippage of the compressor clutch.
6. Check the drive belt tension.
INSUFFICIENT COOLING ”QUICK
CHECK” PROCEDURE
Perform the following ”hand–feel” procedure to get a quick
idea of whether the A/C system has the proper charge of
Refrigerant–134a. The air temperature must be above
21°C (70°F) for most models.
1. Warm up engine. Run the engine at idle.
2. Open the hood and all the doors.
3. Turn the A/C switch ON.
4. Set the temperature control to the full cold position.
5. Set the blower speed switch on the maximum
speed setting.
6. ”Hand–feel” the temperature of the evaporator out-
let pipe. The pipe should be cold.
7. Check for other problems. Refer to ”Testing the Re-
frigerant System” in this section.
8. Leak check the system. Refer to ”Leak Testing the
Refrigerant System” in this section. If you find a
leak, discharge the system and repair the leak as
required. After completing the repair, evacuate the
system and charge it.
9. If there is no leak, refer to ”Insufficient Cooling
Diagnosis” in this section.

MANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM 7B – 9
DAEWOO V–121 BL4
A/C PERFORMANCE TEST
RELATIVE
HUMIDITY
( % )AMBIENT AIR
TEMPERATURELOW SIDE
PRESSUREENGINE
SPEED
(RPM)CENTER DUCT
AIR
TEMPERATUREHIGH SIDE
PRESSURE
°C°FPsiKpa°C°FPsiKpa
2170261797451601103
2027812416520008462121462
3290261799482771910
381003322814573332296
2170261797451601103
3027812416520008462201517
32902718610502831951
381003423415593492406
217026179846162111 7
4027812617920009482271565
32902920011522952034
381003725517633642510
217026179846162111 7
5027812617920009482351620
32903222113553042096
381007149019663802620
2170271868461651138
6027812617920009482461696
32903423415593242234
381004430322723932710
2170271869481711179
70278128193200010502601793
32903624816613302275
381004732424754012765
2170271869481781227
80278130207200012542661834
32903725517633392337
2170271869481781227
90278130207200012542721875
32903826218643402344
* Test Conditions : Doors & hood opened, A/C ON, Recirculation mode, Full Cool with maximum Blower speed, No Sun-
light, Wind velocity at 8km/h (5 mph).

7B – 10IMANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
PRESSURE–TEMPERATURE RELATIONSHIP OF R–134A
Temperature
°C (°F)*Pressure
kPa (psi)*Temperature
°C (°F)*Pressure
kPa (psi)*
–8 (17.6)113.1 (16.4)9 (48.2)296.2 (43.0)
–7 (19.4)121.5 (17.6)10 (50.0)309.6 (44.9)
–6 (21.2)130.2 (18.9)15 (59.0)383.7 (55.7)
–5 (23.0)139.1 (20.2)20 (68.0)467.7 (67.8)
–4 (24.8)148.4 (21.5)25 (77.0)567.5 (82.3)
–3 (26.6)157.9 (22.9)30 (86.0)667.8 (96.9)
–2 (28.4)167.6 (24.3)35 (95.0)785.6 (113.9)
–1 (30.2)177.8 (25.8)40 (104.0)916.4 (133.0)
0 (32.0)188.2 (27.3)45 (113.0)1 062.2 (154.0)
1 (33.8)198.8 (28.8)50 (122.0)1 222.1 (177.2)
2 (35.6)209.9 (30.4)55 (131.0)1 398.2 (202.8)
3 (37.4)221.2 (32.1)60 (140.0)1 589.6 (230.5)
4 (39.2)232.9 (33.8)65 (149.0)1 799.0 (260.9)
5 (41.0)245.0 (35.5)70 (158.0)2 026.6 (293.9)
6 (42.8)257.4 (37.3)75 (167.0)2 272.2 (329.5)
7 (44.6)269.8 (39.1)80 (176.0)2 544.0 (369.0)
8 (46.4)282.9 (41.0)––
* All calculated values are rounded to one decimal place.
Evaporator Range: From –7 to 7°C (19.4 to 44.6°F), the temperatures represent the gas temperatures inside the coil
and not on the coil surfaces. Add 2 to 6°C (4 to 11°F) to the coil and air–off temperatures.
Condenser Range: From 45 to 70°C (113°to 158°F), the temperatures are not ambient. Add 19 to 22°C (34 to 40°C)
to the ambient temperatures for proper heat transfer. Then refer to the pressure chart.
Example:
32°C (90°F) Ambient temperature + 22°C (40°F) = 54°C (130°F)
Condenser temperature, which yields 1 379 kPa (200 psi), based on 50 km/h (31 mph) airflow.

MANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM 7B – 11
DAEWOO V–121 BL4
LEAK TESTING REFRIGERANT
SYSTEM
Test for leaks whenever you suspect a refrigerant leak in
the system. You should also test for leaks whenever you
perform a service operation which results in disturbing the
lines or the connections. Leaks are commonly found at the
refrigerant fittings or at the connections. Leaks are com-
monly caused by the following problems:
S Improper torque.
S Damaged O–ring seals.
S Dirt or lint on the O–ring seals.
Liquid Leak Detectors
Use a liquid leak detector solution on locations such as fit-
tings. Apply the solution to the area in question with the
swab that is supplied with the solution. Look for bubbles
to appear. This will indicate the existence and the location
of any leak.
For areas where this is not practical, such as sections of
the evaporator and the condenser, an electronic leak de-
tector is more useful.
Electronic Leak Detectors
Follow the manufacturer’s instructions for calibration, op-
eration, and maintenance of an electronic leak detector.
Battery condition is especially important to the accuracy
of a portable model. Set the detector to R–134a before be-
ginning the test.
Notice : Electronic leak detectors are sensitive to wind-
shield washing solutions, solvents and cleaners, and cer-
tain vehicle adhesives. Surfaces must be clean to prevent
false readings. Make sure that all surfaces are dry to pre-
vent damage to the detector.
General Testing Instructions
1. Follow the entire path of the refrigerant system.
2. Completely circle each joint at 25 to 50 mm (1 to 2
inches) per second.
3. Hold the probe tip within 6 mm (1/4 inch) of the sur-
face.4. Do not block the air intake.
5. The audible tone changes from 1 to 2 clicks per
second into a solid alarm if there is a leak. Adjust
the balance control to maintain 1 to 2 clicks per
second.
6. Test all of the following areas, even after one leak
has been confirmed:
S Evaporator inlet and outlet.
S Receiver–drier inlet and outlet.
S Condenser inlet and outlet.
S Brazed and welded areas.
S Damaged areas.
S Hose couplings.
S Compressor rear head.
S All fittings and joints.
Testing Service Ports/Access Valves
The sealing caps provide protection for the service ports.
Make sure that these caps are not missing or loose. Al-
ways use the correct cap for each port.
Testing the Evaporator Core
Leaks in the evaporator core are difficult to find. Test the
evaporator core using the following procedure:
1. Run the blower fan at the maximum speed setting
for at least 15 minutes.
2. Turn the blower OFF.
3. Wait for 10 minutes.
4. Remove the blower motor resistor. Refer to Section
7A, Heating and Ventilation System.
5. Insert the leak detector probe as close as possible
to the evaporator core. The detector will indicate a
leak with a solid alarm.
6. Use a flashlight to search for refrigerant oil on the
core surface.
Testing the Compressor Shaft Seal
1. Blow shop air behind and in front of the compressor
clutch/pulley for at least 15 seconds.
2. Wait 1 to 2 minutes.
3. Probe the area in front of the pulley. If the detector
emits a solid alarm, there is a leak.

7B – 12IMANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
V5 SYSTEM AIR CONDITIONING DIAGNOSIS
INSUFFICIENT COOLING DIAGNOSIS
Test Description
The numbers below refer to steps on the diagnostic table.
13. See the Important below.
32. See the Important below.Important : Perform this test under garage conditions with
the air temperature at 21–32°C (70–90°F), and no sun
load. Follow this test carefully for accurate results.
Important : Perform this test exactly as described to ob-
tain accurate results.
Step
ActionValue(s)YesNo
1Record the customer’s complaint.
Can you verify the customer’s complaint?–Go to Step 2System OK
21. Check the A/C fuse.
2. Check the blower fan operation.
3. Check the engine cooling fan operation.
4. Check the A/C compressor belt.
5. Check the A/C condenser for restricted airflow.
6. Check the clutch coil connection.
7. Repair or replace any components as needed.
8. Check the discharge air temperature with the
A/C turned ON.
Is the discharge air temperature normal?At least 7°C
(12°F) below
ambient air
temperatureSystem OKGo to Step 3
31. Turn the ignition switch to LOCK.
2. Connect the high– and the low–pressure
gauges.
Are both pressures within the value specified?69–345 kPa
(10–50 psi)Go to Step 4Go to Step 5
41. Check the A/C system for leaks.
2. Repair any refrigerant leaks as needed.
3. Recover, evacuate, and recharge the A/C sys-
tem.
4. Observe the two pressure gauges.
Are both pressures above the value specified?345 kPa
(50 psi)Go to Step 7–
5Observe the two pressure gauges.
Are both pressures below the value specified?69 kPa
(10 psi)Go to Step 6Go to Step 7
61. Add 0.45 kg (1 pound) of refrigerant R–134a.
2. Check the A/C system for leaks.
3. Repair any refrigerant leaks, as needed.
4. Recover, evacuate, and recharge the A/C sys-
tem.
5. Observe the two pressure gauges.
Are both pressures above the value specified?345 kPa
(50 psi)Go to Step 7–
71. Start the engine and allow it to run at idle.
2. Set the A/C controls to the following positions:
S The A/C switch to the ON.
S The fresh air control switch to fresh air (in-
dicator lamp OFF).
S The blower motor to 4.
S The temperature to full cold.
Does the A/C compressor clutch engage?–Go to Step 8Go to Step 10

MANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM 7B – 13
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
81. Check for a knocking noise from the A/C com-
pressor.
2. Cycle the A/C compressor ON and OFF in or-
der to verify the source of the noise.
Do you hear a loud knocking noise?–Go to Step 9Go to Step 13
91. Recover the A/C system refrigerant.
2. Replace the A/C compressor.
3. Evacuate and recharge the A/C system.
4. Check the A/C system for leaks.
Is the compressor running normally?–Go to Step 13–
101. Turn the ignition switch to LOCK.
2. Disconnect the A/C compressor clutch coil con-
nector.
3. Connect a jumper wire from ground to one A/C
compressor clutch coil terminal.
4. Connect a fused jumper wire from the positive
battery terminal to the other A/C compressor
clutch coil terminal.
Does the A/C clutch engage?–Go to Step 11Go to Step 12
11Repair the electrical circuit to the A/C compressor
clutch coil.
Does the A/C clutch engage?–Go to Step 8–
12Replace the A/C compressor clutch coil.
Does the A/C clutch engage?–Go to Step 8–
131. Close all of the vehicle’s windows and doors.
2. Set the A/C controls to the following positions:
S The A/C switch to the ON position.
S The fresh air control switch to fresh air.
S The blower motor to 4.
S The temperature to full cold.
3. Start the engine and allow it to run at idle for 5
minutes.
4. Feel the evaporator inlet and outlet pipes.
Is there a noticeable difference in the temperature of
the evaporator inlet and outlet pipes?–Go to Step 15Go to Step 14
141. Turn the ignition switch to LOCK.
2. Recover the A/C system refrigerant.
3. Examine the high–pressure pipe for an ob-
struction.
4. Examine the expansion valve for an obstruction
or a malfunction.
5. Repair the obstruction or replace the expansion
valve as needed.
6. Evacuate and recharge the A/C system.
7. Check the A/C system for leaks.
8. Note the discharge air temperature with the
A/C ON.
Is the discharge temperature normal?At least 7°C
(12°F) below
ambient air
temperatureGo to Step 15Go to Step 13

7B – 14IMANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
151. Record the low– and the high–side pressures
after the A/C system has been operating for 5
minutes or more with the engine cooling fan
ON.
2. Locate the intersection of the low– and the high
side pressures. Refer to ”Low– and High–Side
Pressure Relationship Chart” in this section.
Do the low– and the high–side pressures intersect
in the white area of the chart?–System OKGo to Step 16
16Check the high– and the low–side pressures.
Do the low– and the high–side pressures intersect
in the grey area of the chart?–Go to Step 17Go to Step 20
17Feel the liquid pipe between the condenser and the
expansion valve.
Is the pipe cold?–Go to Step 18Go to Step 19
181. Examine the condenser for any restriction of
the airflow.
2. Check the cooling fans for proper operation.
3. Remove the restriction or repair the fans, as
required.
Is the pipe temperature normal now?At least 7°C
(12°F) below
ambient air
temperatureGo to Step 13–
191. Recover, evacuate, and recharge the A/C sys-
tem.
2. Check the A/C system for leaks.
Is the system free from leaks?–Go to Step 13–
20Observe the readings on the pressure gauges.
Are the A/C compressor high– and the low–side
pressures within the specified value of each other?207 kPa
(30 psi)Go to Step 21Go to Step 26
211. Run the engine at 3,000 rpm.
2. Set the A/C controls to the following positions:
S The A/C switch to the ON.
S The fresh air control switch to fresh air.
S The blower motor to 4.
S The temperature to full cold.
3. Close all of the vehicle’s windows and doors.
4. Turn the A/C switch ON and OFF every 20
seconds for 3 minutes.
Are the A/C compressor high– and the low–side
pressures within the specified value of each other?207 kPa
(30 psi)Go to Step 22Go to Step 13
22Observe the pressure rise on both gauges and the
temperatures of both the compressor suction pipe
and the discharge pipe.
Is the pressure rise on both gauges slow and the
suction pipe warm with the discharge pipe very hot?–Go to Step 25Go to Step 23
231. Turn the ignition switch to LOCK.
2. Make sure the compressor clutch is disen-
gaged.
3. Attempt to turn the clutch driver (not the
pulley).
Can you turn the clutch driver freely by hand?–Go to Step 25Go to Step 24

MANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM 7B – 15
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
241. Start the engine.
2. Observe the low–side pressure gauge while
running the engine between 3,000 and 3,800
rpm.
Does the low–side pressure rise rapidly?–Go to Step 32Go to Step 25
251. Recover the A/C system refrigerant.
2. Replace the A/C compressor.
3. Evacuate and recharge the A/C system.
Is the compressor functioning normally?–Go to Step 13–
26Check the low–side pressure.
Is the low–side pressure within the specified value?172–241 kPa
(25–35 psi)Go to Step 27Go to Step 32
27Feel the high–side pipe leading up to the expansion
valve connecting block.
Is the pipe cold before the connecting block?–Go to Step 28Go to Step 29
281. Check for a restriction in the high–side pipe
before the expansion valve.
2. Repair or replace the high–side pipe.
Is the pipe performing normally?–Go to Step 13–
29Add the specified amount of refrigerant to the A/C
system.
Does the cooling performance improve?0.40 kg
(14 ounces)Go to Step 30Go to Step 31
301. Check the A/C system for leaks.
2. Repair any refrigerant leaks, as needed.
3. Evacuate and recharge the A/C system.
4. Check the A/C system for leaks.
Is the system free from leaks?–Go to Step 13–
311. Recover the refrigerant.
2. Check the expansion valve for obstructions.
3. Repair or replace the expansion valve, as re-
quired.
4. Evacuate and recharge the system.
5. Check the A/C system for leaks.
Is the system free from leaks?–Go to Step 13–
321. Run the engine for 5 minutes at 2,000 rpm.
2. Set the A/C controls to the following positions:
S The A/C switch to the ON position.
S The fresh air control switch to recirculate
(indicator lamp ON).
S The blower motor to 1.
S The temperature to full cold.
3. Close all of the vehicle’s windows and doors.
4. Open the vehicle hood.
Is the low–side pressure within the specified value?172–241 kPa
(25–35 psi)Go to Step 13Go to Step 33
331. Recover the A/C system refrigerant.
2. Replace the A/C compressor control valve.
3. Evacuate and recharge the A/C system.
4. Check the A/C system for leaks.
Is the system free from leaks?–Go to Step 13–

7B – 16IMANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
SYMPTOM DIAGNOSIS
PRESSURE TEST CHART (R–134A SYSTEM)
Test ResultsRelated SymptiomsProbable CauseRemedy
Discharge (high)
pressure abnormally
highAfter stopping the compres-
sor, the pressure drops
about 299 kPa (28 psig)
quickly, then falls gradually.Air in the system.Recover, evacuate and re-
charge the system with the
specified amount of refrig-
erant.
The condenser is exces-
sively hot.Excessive refrigerant in the sys-
tem.Recover, evacuate and re-
charge the system with the
specified amount of refrig-
erant.
Reduced or no airflow
through the condenser.Condenser or the radiator fins are
clogged.Clean the condenser or the
radiator fins.
Condenser or the radiator fan is
not working properly.Check the voltage and the
fan rpm.
Check the fan direction.
Line to the condenser is ex-
cessively hot.Restricted flow of refrigerant in
the system.Locate and repair the re-
striction.
Discharge pressure
abnormally lowThe condenser is not hot.Insufficient refrigerant in the sys-
tem.Check the system for a
leak.
Charge the system.
High and low pressures are
balanced soon after stop-
ping the compressor.Faulty compressor pressure relief
valve.Repair or replace the com-
pressor.
Low–side pressure is high-
er than normal.Faulty compressor seal.
The outlet of the expansion
valve is not frosted.Faulty expansion valve.Replace the expansion
valve.
Low pressure gauge indi-
cates vacuum.Moisture in the system.Recover, evacuate, and re-
charge the system.
Suction (low) pres-
sure abnormally lowCondenser is not hot.Insufficient refrigerant in the sys-
tem.Repair the leaks.
Recover, evacuate, and re-
charge the system.
The expansion valve is not
frosted and the lowpressure
line is not cold.Faulty expansion valve.Replace the expansion
valve.
Low–Pressure gauge indi-
cates a vacuum.Frozen expansion valve.
Discharge temperature is
low and the airflow from the
vents is restricted.Evaporator is frozen.Clear the restricted evapo-
rator case drain.
The expansion valve is
frosted.Expansion valve is clogged.Clean or replace the expan-
sion valve.
The receiver–dryer outlet is
cool and the inlet is warm.Receiver–dryer is clogged.Replace the receiver–dryer.
Suction pressure ab-
normally highLow–pressure hose and
check joint are cooler than
the temperature around the
evaporator.Expansion valve is opened for too
long.Replace the expansion
valve.
Capillary tube is loose.

MANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM 7B – 17
DAEWOO V–121 BL4
Test ResultsRemedy Probable Cause Related Symptioms
Suction pressure ab-
normally highSuction pressure is lowered
when the condenser is
cooled by water.Excessive refrigerant in the sys-
tem.Recover, evacuate, and re-
charge the system.
High and low pressure are
equalized as soon as the
compressor is stopped and
both gauges fluctuate while
the compressor is running.Faulty gasket.Repair or replace the com-
pressor.
Faulty high–pressure valve. (V5
compressor only)
Foreign particles stuck in the
high–pressure valve. (V5 com-
pressor only)
Suction and dis-
charge pressure ab-
ll hi h
Reduced airflow through
the condenser.Clogged condenser or radiator
fins.Clean the condenser and
the radiator.
g
normally highRadiator cooling fans working im-
properly.Check the voltage and the
radiator cooling fan rpm.
Check the fan direction.
Condenser is excessively
hot.Excessive refrigerant in the sys-
tem.Recover, evacuate, and re-
charge the system.
Suction and dis-
charge pressure ab-
normally lowLow–pressure hose and
metal end areas are cooler
than the evaporator.Clogged or kinked low–pressure
hose.Repair or replace the low–
pressure hose.
Temperature around the ex-
pansion valve is low
compared to that around
the receiver–dryer.Clogged high–pressure line.Repair or replace the high–
pressure line.
Refrigerant leaksThe compressor clutch is
dirty.Leaking compressor shaft seal.Repair or replace the com-
pressor.
The compressor bolts are
dirty.Leaking around a compressor
housing bolt.Tighten the bolt(s) or re-
place the compressor.
The compressor gasket is
wet with oil.Leaking compressor gasket.Repair or replace the com-
pressor.