2004 DAEWOO LACETTI heater

SECTION : 7A
HEATING AND VENTILATION SYSTEM
CAUTION : Disconnect the negative battery cable before removing or installing any electrical unit or when a tool
or equipment could easily come in contact with exposed electrical terminals. Disconnecting this cable will help
prevent personal injury and damage to the vehicle. The ignition must also be in LOCK unless otherwise noted.
TABLE OF CONTENTS
SPECIFICATIONS7A–1 . . . . . . . . . . . . . . . . . . . . . . . . . .
Heater Temperature Specifications 7A–1. . . . . . . . . . .
Fastener Tightening Specifications 7A–1. . . . . . . . . . .
SCHEMATIC AND ROUTING DIAGRAMS7A–3 . . . . .
Non–A/C Diagrams 7A–3. . . . . . . . . . . . . . . . . . . . . . . .
Airflow – Typical 7A–4. . . . . . . . . . . . . . . . . . . . . . . . . . .
Airflow with Rear Heating Duct 7A–5. . . . . . . . . . . . . .
DIAGNOSIS7A–6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
HEATER SYSTEM 7A–6. . . . . . . . . . . . . . . . . . . . . . . . . .
Insufficient Heating or Defrosting 7A–6. . . . . . . . . . . . .
Blower Electrical 7A–9. . . . . . . . . . . . . . . . . . . . . . . . . . .
Improper Air delivery or No Mode Shift 7A–11. . . . . .
Too Much Heat 7A–13. . . . . . . . . . . . . . . . . . . . . . . . . . .
Controls 7A–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Noise 7A–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . MAINTENANCE AND REPAIR7A–18 . . . . . . . . . . . . . .
ON–VEHICLE SERVICE 7A–18. . . . . . . . . . . . . . . . . . . .
Temperature Cable Adjustment 7A–18. . . . . . . . . . . . .
Temperature Control Cable 7A–18. . . . . . . . . . . . . . . . .
Control Assembly 7A–20. . . . . . . . . . . . . . . . . . . . . . . . .
Control Assembly Knob Lighting 7A–21. . . . . . . . . . . .
Heater/Air Distributor Case Assembly 7A–21. . . . . . .
Blower Motor 7A–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
High–Blower Relay 7A–24. . . . . . . . . . . . . . . . . . . . . . . .
Blower Resistor 7A–25. . . . . . . . . . . . . . . . . . . . . . . . . .
Heater Hoses 7A–25. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heater Core 7A–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GENERAL DESCRIPTION AND SYSTEM
OPERATION7A–28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heating and Ventilation Systems 7A–28. . . . . . . . . . . .
SPECIFICATIONS
HEATER TEMPERATURE SPECIFICATIONS
Ambient Air TemperatureHeater Outlet Air Temperature
–18°C (0°F)54°C (129°F)
– 4°C (25°F)59°C (138°F)
10°C (50°F)64°C (147°F)
24°C (75°F)68°C (154°F)
FASTENER TIGHTENING SPECIFICATIONS
ApplicationNSmLb–FtLb–In
Blower Motor–to–A/C Assembly Screws1.2–11
Blower Motor Resistor Screws1.2–11
Blower Motor Retaining Screws1.2–11
Controller Retaining Screws2–18
Heater/Air Distributor Case Assembly Screw4–35

7A – 2IHEATING AND VENTILATION SYSTEM
DAEWOO V–121 BL4
Application Lb–InLb–Ft NSm
Heater Core Cover Screws1.2–11
Heater Core Housing–to–Evaporator Housing Screws1.2–11

7A – 6IHEATING AND VENTILATION SYSTEM
DAEWOO V–121 BL4
DIAGNOSIS
HEATER SYSTEM
INSUFFICIENT HEATING OR DEFROSTING
CAUTION : The cooling system is pressurized when hot. Injury can result from removing the surge tank cap be-
fore the engine is sufficiently cool.
Step
ActionValue(s)YesNo
1Verify the customer’s complaint.
Are the customer’s concerns verified?–Go to Step 2System OK
2Check the coolant level.
Is the coolant level correct?–Go to Step 4Go to Step 3
3Add coolant as needed.
Is the repair complete?–System OKGo to Step 4
4Check the timing belt for tension or damage.
Are the drive belts OK?–Go to Step 6Go to Step 5
5Correct any problem with the timing belt.
Is the repair complete?–System OKGo to Step 6
6Check the coolant hoses for leaks or kinks.
Are the coolant hoses OK?–Go to Step 8Go to Step 7
7Repair any problem with the coolant hoses.
Is the repair complete?–System OKGo to Step 8
8Check the surge tank cap. Refer to Section 2D, En-
gine Cooling.
Is the surge tank cap OK?–Go to Step 10Go to Step 9
9Repair or replace the surge tank cap as needed.
Is the repair complete?–System OKGo to Step 10
101. Turn the A/C switch OFF on vehicles equipped
with air conditioning (A/C).
2. Set the blower motor switch on maximum
speed.
3. Set the heater control to full hot.
4. Turn the ignition ON.
5. Check for airflow from the vent outlet.
Is there heavy airflow from the heater outlet?–Go to Step 11Go to Step 26
11Check for a change in the airflow at various blower
speeds.
Does the blower speed increase as the switch is
turned from 1 to 4.–Go to Step 12Go to ”Blower
Electrical
(Manual and
Non–A/C)”
121. Turn the A/C switch OFF.
2. Set the temperature lever to full hot.
3. Set the blower motor switch on maximum
speed.
4. With the engine sufficiently cool, remove the
surge tank cap.
5. Start the vehicle and idle the engine.
6. Watch for the flow of the coolant.
Is the coolant flow visible?–Go to Step 14Go to Step 13

HEATING AND VENTILATION SYSTEM 7A – 7
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
131. Check for the following problems:
S Restriction in the cooling system.
S Failed water pump impeller.
S Faulty thermostat.
2. Make repairs to the cooling system, as needed.
Are the repairs complete?–System OKGo to Step 14
141. Install the surge tank cap.
2. With the ignition ON, allow the engine to warm
up for about 20 minutes. Drive the vehicle at 48
km/h (30 mph).
3. Use a thermometer to measure the ambient air
temperature and the discharge air temperature
at the heater outlet.
Does the heater output meet the minimum values
given?Go to ”Heater
Temperature
Specifications”Go to Step 15Go to Step 16
151. Check the vehicle for cold air leaks at the fol-
lowing locations:
S Dash.
S Heater cases.
S Vents.
2. Check under the seat for obstructions.
3. Repair any leaks or obstructions.
Are the repairs complete?–System OK–
161. Turn the ignition OFF.
2. Turn the temperature control knob to full cold,
then rapidly to full hot.
3. Listen for the sound of the temperature door
slam just before it reaches the end of the travel
range of the control knob.
Does the door slam?–Go to Step 18Go to Step 17
171. Check the following aspects of the temperature
door:
S Travel.
S Cables.
S Linkage.
2. Verify the accuracy of the temperature controls
at full hot.
3. Verify the accuracy of the temperature controls
at full cold.
Is the repair complete?–System OK–
181. Set the temperature control knob to full hot.
2. Start the vehicle.
3. Check the temperature of the heater inlet hose
and the heater outlet hose by feel. The air tem-
perature around the hoses should be at least
29°C (84°F).
Is the heater inlet hose hot and the heater outlet
hose warm?–Go to Step 19Go to Step 22
19Check the thermostat. Refer to 2D, Engine Cooling.
Is the thermostat installed and seated properly?–Go to Step 20Go to Step 21

7A – 8IHEATING AND VENTILATION SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
20Replace the thermostat. Refer to Section 2D, En-
gine Cooling.
Is the repair complete?–System OK–
21Reinstall the thermostat.
Is the repair complete?–System OK–
22Inspect the heater hoses for proper installation.
Are the heater hoses reversed?–Go to Step 23Go to Step 24
23Reinstall the heater hoses properly.
Is the repair complete?–System OK–
241. Back flush the heater core.
2. Drain the cooling system.
3. Replace the coolant.
4. Warm the engine to an average operating tem-
perature.
5. Feel the heater inlet hose and the heater outlet
hose.
Is the heater inlet hose hot and the heater outlet
hose warm?–System OKGo to Step 25
25Replace the heater core.
Is the repair complete?–System OK–
26Recheck the system using the ”Control Settings/
Correct Results” tests. Refer to ”Improper Air Deliv-
ery or No Mode Shift” in this section.
Is the repair complete?–System OKGo to Step 27
27Check for airflow from the defroster or the vent out-
lets.
Is there high airflow from the defroster or vent out-
lets?–Go to Step 28Go to Step 29
281. Check the heater door at the floor and the vent
door to get the proper airflow and to verify
proper operation.
2. Repair as required.
Is the repair complete?–System OK–
29Switch the mode knob to defrost.
Is the defroster airflow OK?–Go to Step 30Go to Step 31
301. Remove the heater outlet and check for ob-
structions.
2. Remove any obstructions in the heater outlet.
Is the repair complete?–System OK–
31Check for airflow change at various blower speeds.
Does the blower speed increase as the control is
turned from 1 to 4?–Go to Step 32Go to ”Blower
Electrical
(Manual and
Non–A/C)”
32Check for obstructions in the system at the blower
inlet and at the air filter, if the vehicle is equipped with
one.
Are there any obstructions?–Go to Step 33Go to Step 34
33Remove the obstructions in the system at the blower
inlet or replace a clogged filter.
Is the repair complete?–System OK–

HEATING AND VENTILATION SYSTEM 7A – 9
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
341. Set the blower on maximum speed.
2. Rotate the temperature control from full hot to
full cold.
3. Listen for an airflow change.
Does the airflow change?–Go to Step 35Go to Step 36
351. Check the following aspects of the temperature
door:
S Travel.
S Cables.
S Linkage.
S Control.
2. Verify the accuracy of the temperature control
at full hot.
Is the repair complete?–Go to Step 1–
361. Check the system for any obstruction between
the blower and the system outlets.
2. Remove any obstruction.
Is the repair complete?–Go to Step 1–
BLOWER ELECTRICAL
StepActionValue(s)YesNo
1Verify the customer’s complaint.
Are the customer’s concerns verified?–Go to Step 2System OK
2Turn the blower ON.
Does the blower run at any speed?–Go to Step 14Go to Step 3
31. Disconnect the power connector from the blow-
er motor under the dashboard on the passen-
ger side of the vehicle.
2. Turn the ignition ON.
3. Turn the blower ON.
4. Test for voltage on the connector. The terminal
connected to the violet wire is positive and the
terminal connected to the black wire is nega-
tive.
Is this voltage present?11–14vGo to Step 4Go to Step 5
4Replace the blower motor.
Is the repair complete?–System OK–
5Check fuse F7 in the I/P fuse block in the engine fuse
block.
Is the fuse blown?–Go to Step 6Go to Step 7
61. Turn the ignition ON.
2. Use a short detector to locate a possible short
in the following locations:
S Fuse panel–to–blower speed switch.
S Blower speed switch–to–heater resistor
block.
S Heater resistor block–to–blower motor.
S Blower speed switch–to–blower HI relay.
3. Repair any short.
4. Replace any blown fuse.
Is the repair complete?–System OK–

HEATING AND VENTILATION SYSTEM 7A – 11
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
211. Disconnect the resistor block connector.
2. Connect one lead of a self–powered test light
to any single lead on the resistor block. Use
the other lead to probe each of the other two
terminals.
Does the test light illuminate on all terminals?–Go to Step 23Go to Step 22
22Replace the resistor block.
Is the repair complete?–System OK–
231. Turn the ignition to LOCK.
2. Disconnect the connector from the resistor
block.
3. Connect a jumper lead from the positive termi-
nal on the battery to any wire terminal in the
connector.
4. Use a 12–volt test light to check for voltage
from the corresponding wire on the blower
speed switch.
5. Repeat the same test on the other wires.
Does the lamp light on all three wires?–Go to Step 25Go to Step 24
24Replace the blower speed switch.
Is the repair complete?–System OK–
25Repair the open in the affected wire.
Is the repair complete?–System OK–
IMPROPER AIR DELIVERY OR NO MODE SHIFT
This procedure provides a test of all functions of the heater/defroster unit.
1. Warm up the vehicle.
2. Keep the engine running.
3. Perform the tests outlined in the table below and look for the results indicated.
CONTROL SETTINGS
CORRECT RESULTS
Mode
KnobTe m p
Contro
lBlower
Motor
SwitchBlower
SpeedPower
Vent
OutletFloor
OutletDefrost
OutletSide
Window
Outlet
VentColdOffOffNo
AirflowNo
AirflowNo
AirflowNo
Airflow
VentCold4HighAmbient
AirflowNo
AirflowNo
AirflowNo
Airflow
FloorCold to
Hot4HighNo
AirflowCold to Hot
AirflowMinimum
Cold to Hot
AirflowMinimum
Cold to Hot
Airflow
De-
frosterCold to
Hot4HighNo
AirflowMinimum
Cold to Hot
AirflowCold to Hot
AirflowMinimum
Cold to Hot
Airflow
If any of these settings does not produce the correct results, perform the following diagnostic procedure.

7A – 12IHEATING AND VENTILATION SYSTEM
DAEWOO V–121 BL4
StepActionValue(s)YesNo
1Verify the customer’s complaint.
Are the customer’s concerns verified?Go to Step 2System OK
2S Examine the affected door in the unit for proper
attachment to the vacuum actuator.
S Check the actuator connection to the door.
S Check that the vacuum hose is properly con-
nected.
Is everything connected properly?–Go to Step 4Go to Step 3
3Repair as necessary.
Is the repair complete?–System OK–
41. Disconnect the actuator at the door.
2. Check the range of the door travel and the ef-
fort required to move it.
Does the door move freely through its entire range
of travel so that it can close at both ends of the
range?–Go to Step 5Go to Step 3
5Check the travel of the actuator by turning the con-
trol knob with the engine running.
Is the actuator travel OK?–Go to Step 6Go to Step 7
61. Reinstall the actuator.
2. Recheck the system using the ”Control Set-
tings/Correct Results” tests in this procedure.
Does the system perform properly?–System OKGo to Step 9
71. Check the vacuum hose at the control.
2. Check for a broken control.
Is there a problem with the vacuum hose or the con-
trol?–Go to Step 8Go to Step 9
8Repair the vacuum hose or the control as necessary.
Is the repair complete?–System OKGo to Step 9
9Recheck the system using the ”Control Settings/
Correct Results” tests in this procedure.
Is the repair complete?–System OKGo to Step 10
10Check for airflow from the defroster or the vent out-
lets.
Is there high airflow from the defroster or the vent
outlets?–Go to Step 11Go to Step 12
11Adjust the heater door at the floor and the vent door
to get the proper airflow.
Is the repair complete?–System OK–
12Switch the mode knob to defrost.
Is the defroster airflow OK?–Go to Step 13Go to Step 14
131. Remove the heater outlet.
2. Check the heater outlet for obstructions.
3. Remove any obstructions in the heater outlet.
Is the repair complete?–System OK–
14Check the blower speeds for change in the airflow.
Does the blower speed increase as the control is
turned from 1 to 4?–Go to Step 15Go to ”Blower
Electrical
(Manual and
Non–A/C)”