2004 DAEWOO NUBIRA heating

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–

7A – 10IHEATING AND VENTILATION SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
71. Turn the ignition ON.
2. Set the blower switch on 4.
3. Check the blower motor ground.
Is ground OK?–Go to Step 9Go to Step 8
8Repair the blower motor ground.
Is the repair complete?–System OK–
9Check the motor connector with a 12–volt test light.
Does the test light come on?–Go to Step 10Go to Step 11
10Repair the open in the feed wire from the resistor
block to the blower motor.
Is the repair complete?–System OK–
11Use the 12–volt test light to check the power feed
terminal on the blower speed switch.
Does the light come on?–Go to Step 12Go to Step 13
12Replace the blower speed switch.
Is the repair complete?–System OK–
13Repair the open in the power wire from the blower
speed switch to the fuse panel.
Is the repair complete?–System OK–
14Turn the blower on speed 4.
Does the blower fail to operate at speed 4?–Go to Step 15Go to Step 21
15Check fuse EF3 in the engine fuse block.
Is the fuse blown?–Go to Step 16Go to Step 17
161. Turn the ignition ON.
2. Turn the blower motor switch to 4.
3. Use a short detector to locate a possible short
in the following locations:
S Engine fuse panel–to–blower HI relay.
S Blower HI relay–to–blower motor.
4. Repair any short.
5. Replace the EF3 fuse.
Is the repair complete?–System OK–
171. Turn the ignition switch ON.
2. Set the blower switch to 4.
3. Check for 12 volts on the blower HI relay coil
terminal from the blower speed switch terminal
A7.
Is this voltage present?–Go to Step 18Go to Step 19
18Replace the blower speed switch.
Is the repair complete?–System OK–
191. Turn the ignition OFF.
2. Check for opens in the following locations:
S EF3 fuse–to–blower HI relay.
S Blower speed switch–to–blower– HI relay.
S Blower HI relay–to–ground.
S Blower HI relay–to–blower motor.
3. Repair any opens.
Is the repair complete?–System OKGo to Step 20
20Replace the blower HI relay.
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)”

HEATING AND VENTILATION SYSTEM 7A – 13
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
151. Check for obstructions in the system at the
blower inlet and check the air filter if the vehicle
is so equipped.
2. Remove any obstructions at the blower inlet
and replace the filter if it is clogged.
Is the repair complete?–System OKGo to Step 16
161. Set the blower on 4.
2. Rotate the temperature control from full hot to
full cold.
3. Listen for an airflow change.
Does the airflow change?–Go to Step 17Go to Step 18
171. Check the temperature door, the cable, the
linkage, and the control.
2. Adjust the temperature control to full hot.
Is the repair complete?–System OK–
181. Check the system for any obstruction between
the blower and the system outlets.
2. Remove any obstruction between the blower
and the system outlets.
Is the repair complete?–System OK–
TOO MUCH HEAT
StepActionValue(s)YesNo
1Verify the customer’s complaint.
Are the customer’s concerns verified?–Go to Step 2System OK
2Is there too much heat when the mode switch is in
the floor position?–Go to Step 3Go to Step 9
3Is there objectionable defroster bleed?–Go to Step 4Go to Step 5
41. Check the door travel, the cable, the vacuum
actuators, and the linkage for the heater and
the defroster.
2. Adjust or repair, as required.
Is the repair complete?–System OK–
51. In vehicles equipped with A/C, set the A/C
switch OFF.
2. In all vehicles, set the blower speed to maxi-
mum.
3. Set the temperature to full hot.
4. Turn the ignition switch ON.
5. Check for airflow from the floor outlets.
6. Check the floor outlet attachment.
Is the airflow high?–Go to Step 6Go to Step 8
6Check for a change in the airflow at different blower
speeds.
Does the airflow change as the setting for the blow-
er–speed switch is scanned?–Go to Step 7 Go to ”Blower
Electrical
(Manual and
Non–A/C)”

7A – 14IHEATING AND VENTILATION SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
71. Check the temperature door travel, the cable,
and the linkage.
2. Adjust to full cold.
3. Check for full hot.
Is the repair complete?–System OK–
8Adjust or repair the floor/defroster and/or the vent/
floor mode.
Is the repair complete?–System OK–
9In the vent position, is the problem objectionable
bleed?–Go to Step 10Go to Step 15
101. Check the system case for leaks.
2. Check the floor outlet attachment.
Are there problems?–Go to Step 11Go to Step 12
11Repair the system case or the floor outlet attach-
ment as required.
Is the repair complete?–System OKGo to Step 12
121. Turn the ignition switch OFF.
2. Turn the temperature control knob to full hot,
then rapidly to full cold.
Do you hear the door slam just before you reach the
end of the control travel?–Go to Step 13Go to Step 14
13Adjust the vent door to vent more.
Is the repair complete?–System OK–
141. Check the temperature door travel, the cables,
and the linkage.
2. Verify that the temperature door goes to full
cold.
3. Check the temperature door for full hot.
Is the temperature door travel correct?–System OK–
151. Set the fresh air/recirculating air control to
fresh air (indicator lamp off).
2. Set the temperature control to full cold.
3. Start the vehicle and allow the engine to warm
up.
4. Measure the air temperature at the blower in-
let, or cowl, and at the vent air outlet inside the
vehicle.
Is the outlet air more than 5°C (41°F) warmer than
the inlet air?–Go to Step 16System OK
161. Check for hot air leaks from the engine
compartment to the blower inlet.
2. Repair, as needed.
Is the repair complete?–System OK–

HEATING AND VENTILATION SYSTEM 7A – 15
DAEWOO V–121 BL4
CONTROLS
StepActionValue(s)YesNo
1Verify the customer’s complaint.
Are the customer’s concerns verified?–Go to Step 2System OK
2Move controls other than the temperature adjust-
ment.
Is an excessive effort required to move the controls?–Go to Step 15Go to Step 3
3Move the temperature control.
Is an excessive effort required to move the controls?–Go to Step 6Go to Step 4
4Move the temperature control.
Does the temperature door move too easily?–Go to Step 5System OK
5Remove the cable from the controller.
Does the control knob turn freely, without the click
stops?–Go to Step 15–
6Check the cables for improper routing, kinks, wiring
interference, or other instrument panel interference.
Is there a problem?–Go to Step 7Go to Step 8
7Repair as needed.
Is the repair complete?–System OK–
81. Remove the cable from the temperature door.
2. Cycle the door manually.
3. Check for door binding.
Is there any door binding?–Go to Step 9Go to Step 12
9Check a binding door for shaft alignment, a bent
shaft, a bent door, or a warped case.
Is the door seal OK?–Go to Step 10Go to Step 11
101. Check a binding door for shaft alignment, a
bent shaft, a bent door, or a warped case.
2. Repair, as needed.
Is the repair complete?–System OK–
11Repair the door seal, as needed.
Is the repair complete?–System OK–
12Check for control binding.
Does the control bind?–Go to Step 14Go to Step 13
131. Reinstall the cable to the door.
2. Check the clearance for the cable–to–dash
components.
3. Repair any interference.
Is the repair complete?–System OK–
141. Remove the cable from the control.
2. Check the control for binding.
Does the control bind?–Go to Step 15Go to Step 16
15Replace the control.
Is the repair complete?–System OK–
16Replace the cable.
Is the repair complete?–System OK–