Page 2078 of 2643
AUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM 7D – 23
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
61. Reconnect the coolant temperature sensor to
the ATC harness.
2. Turn the ignition switch to ON.
3. Observe the temperature display area.
Does this display indicate the continuing presence of
a code 3 condition?–Go to Step 9System OK
71. Pull the ATC controller from the instrument
panel, leaving the wiring harness connected.
2. Measure the voltage between terminals A13
and B9 by backprobing the connectors.
Is the voltage equal to the value specified?< 4 vGo to Step 9Go to Step 8
81. Trace the wiring from controller terminals A13
and B9 to the coolant temperature sensor con-
nector terminals on the ATC harness connec-
tors.
2. Repair any open or high resistance found in the
wiring or connector terminals.
Is the repair complete?–System OK–
9Replace the ATC controller.
Is the repair complete?–System OK–
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7D – 24IAUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
CODE 4 – AIR MIX DOOR ERROR
This code will set if the output of the mix door indicator indicates that the door opening angle is out of range or does not
change value when the door should be moving. This would indicate a short circuit or an open in the sensor or the associated
wiring harness, a door motor that is not operating, or a malfunction of the ATC controller.
Code 4 – Air Mix Door Error
StepActionValue(s)YesNo
11. Disconnect the I/P wiring harness connector
from the air mix door (AMD) motor.
2. Use an ohmmeter to measure the resistance
between terminals 5 and 7 on the AMD motor.
Does the measured resistance indicate an open or
a shorted condition?Open = ,
Short = 0 ΩGo to Step 4Go to Step 2
2Measure the resistance between terminals 2 and 3
on the AMD motor.
Is the resistance equal to the value specified? 3000 ΩGo to Step 3Go to Step 4
3Measure the resistance between terminals 6 and 2
and between terminals 6 and 3 on the AMD motor.
Do these resistances add to approximately the value
measured between terminals 2 and 3? 3000 ΩGo to Step 5Go to Step 4
4Replace the AMD motor.
Is the repair complete?–System OK–
5Check the connector terminals at the AMD motor
and the wiring in the ATC harness.
Is there a problem with any terminal on either the
harness connector or the motor connector or the wir-
ing?–Go to Step 6Go to Step 7
6Repair the problem found with a connector terminal
or the wiring, or replace the motor as required.
Is the repair complete?–System OK–
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AUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM 7D – 25
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
71. Remove the ATC controller from the instrument
panel.
2. Disconnect the harness connectors from the
ATC controller.
3. Examine the connector terminals on the har-
ness connectors and the controller connectors
and the harness wiring.
Is there a problem with any of these connectors or
the wiring?–Go to Step 8Go to Step 9
8Repair the problem found with a connector terminal
or wiring.
Is the repair complete?–System OK–
9Check continuity in the harness between the control-
ler connectors and the AMD motor connector.
S Controller terminal A2 to motor terminal 7.
S Controller terminal A8 to motor terminal 5.
S Controller terminal B6 to motor terminal 2.
S Controller terminal B5 to motor terminal 6.
S Controller terminal B4 to motor terminal 3.
Does the continuity equal the specified value? 0 ΩGo to Step 10Go to Step 11
10Repair the continuity problem.
Is the repair complete?–System OK–
111. Reconnect the AMD motor to the ATC harness.
2. Reconnect the ATC harness connectors to the
controller.
3. Turn the ignition to ON.
4. Use backprobing for voltage measurements.
5. Measure the voltage between ground and ter-
minal B5 at the controller.
Is the voltage equal to the specified value?< 4 vGo to Step 12Go to Step 14
121. Set the temperature controller to 18°C (64°F).
2. Connect a voltmeter between ground and ter-
minal A8 at the controller. It should display
about 12 v.
3. Raise the temperature setting on the controller
to 32°C (90°F).
Does the voltage equal the specified value?Drops from
12 v to 0 vGo to Step 13Go to Step 15
131. Connect a voltmeter between ground and ter-
minal A2 at the controller. It should display
about 12 v.
2. Change the temperature setting to 18°C
(64°F).
Does the voltage equal the specified value?Drops from
12 v to 0 vGo to Step 20Go to Step 15
141. Recheck the wiring harness and the connector
terminals associated with controller terminals
B4, B5, and B6, and AMD motor terminals 2, 6,
and 3.
2. Repair any problem found.
Is the repair complete?–System OK–
15Recheck all wiring circuits between the controller
and the AMD motor.
Is there a problem in the wiring or the connectors?–Go to Step 16Go to Step 17
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7D – 26IAUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
16Repair the problem in the wiring between the ATC
controller and the AMD motor.
Is the repair complete?–System OK–
17Recheck the AMD motor.
Is there a problem in the AMD motor?–Go to Step 18Go to Step 19
18Replace the AMD motor.
Is the repair complete?–System OK–
19Replace the controller.
Is the repair complete?–System OK–
20Observe the operation of the air mix door when the
temperature setting is changed.
Does the door move normally?–Go to Step 22Go to Step 21
21Repair or replace the air mix door.
Is the repair complete?–System OK–
22Observe the operation of the AMD motor when the
temperature setting is changed.
Does the motor operate normally?–Go to Step 24Go to Step 23
23Replace the AMD motor.
Is the repair complete?–System OK–
24Reconnect everything and test the system.
Does code 4 reset?–Go to Step 25System OK
25Replace the controller.
Is the repair complete?–System OK–
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AUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM 7D – 27
DAEWOO V–121 BL4
CODE 5 – SUN SENSOR ERROR
This code will set if the output of the sun sensor indicates a probable short circuit or an open in the sensor or the associated
wiring harness, or a malfunction of the ATC controller.
Code 5 – Sun Sensor Error
StepActionValue(s)YesNo
11. Lift the sun sensor from the top of the dash-
board.
2. Secure the ATC harness below the sun sensor
connector so it cannot fall through the opening
in the top of the dashboard.
3. Disconnect the sun sensor connector from the
ATC harness.
4. Examine the wiring from the sensor to the con-
nector, and examine the connector for any
signs of damage.
5. Measure the resistance between the sun sen-
sor connector terminals.
Is there any sign of damage in the wiring or connec-
tor or does the resistance equal the value specified? 0 WGo to Step 2Go to Step 3
2Repair the damaged wiring or the connector, or re-
place the sun sensor as required.
Is the repair complete?–System OK–
31. Turn the ignition to ON.
2. Measure the voltage between the two sun sen-
sor connector terminals on the ATC harness.
Is the voltage equal to the specified value?< 4 vGo to Step 7Go to Step 4
4Check the terminals on the sun sensor connector.
Is any problem found with the connector?–Go to Step 5Go to Step 6
5Repair the connector terminals or replace the sun
sensor or ATC controller as required.
Is the repair complete?–System OK–
Page 2083 of 2643
7D – 28IAUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
61. Reconnect the sun sensor to the ATC harness.
2. Turn the ignition switch to ON.
3. Observe the temperature display area.
Does this display indicate the continuing presence of
a code 5 condition?–Go to Step 9System OK
71. Pull the ATC controller from the instrument
panel, leaving the wiring harness connected.
2. Measure the voltage between terminals A13
and B10 by backprobing the connectors.
Is the voltage equal to the value specified?< 4 vGo to Step 9Go to Step 8
81. Trace the wiring from controller terminals A13
and B10 to the sun sensor connector terminals
on the ATC harness connectors.
2. Repair any open or high resistance found in the
wiring or connector terminals.
Is the repair complete?–System OK–
9Replace the ATC controller.
Is the repair complete?–System OK–
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AUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM 7D – 29
DAEWOO V–121 BL4
CODE 6 – POWER TRANSISTOR ERROR
StepActionValue(s)YesNo
11. Disconnect the ATC controller connectors A
and B.
2. Disconnect the connectors from the power
transistor.
3. Measure the resistance circuit GRY/BLK from
terminal 4 of the power transistor to terminal
B1 of the ATC controller.
Does the resistance equal the specified value? 0 WGo to Step 2Go to Step 6
2Measure the resistance in the circuit from terminal
1 of the power transistor to terminal B12 of the ATC
controller.
Does the resistance equal the specified value? 0 ΩGo to Step 3Go to Step 6
31. Reconnect the wiring harness to the ATC con-
troller and to the power transistor.
2. Turn the ignition switch to ON.
3. Measure the voltage from ground to terminal
B12 of the ATC controller.
4. Cycle the fan speed controller manually from
the lowest (speed 1) to the highest speed (8).
Do the voltages measured match approximately the
specified values within ±0.5 v?1: 4.0 v
2: 5.0 v
3: 6.0 v
4: 7.0 v
5: 8.0 v
6: 9.0 v
7: 10.0 v
8: Max Hi:Go to Step 4Go to Step 5
4Replace the ATC controller.
Is the repair complete?–System OK–
Page 2085 of 2643
7D – 30IAUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
5Measure the resistance in circuit (Violet) between
terminal 6 of the power transistor and the blower mo-
tor terminal 2.
Does the resistance equal the specified value? 0 ΩGo to Step 7Go to Step 6
6Repair or replace the wiring harness for the circuit
(Violet).
Is the repair complete?–System OK–
7Check the wiring harness of the motor and power
supply.
S Check the blower relay.
S Check fuse EF3.
Is there any problem in the wiring, the relay, or the
fuse?–Go to Step 9Go to Step 8
8Replace the power transistor.
Is the repair complete?–System OK–
9Repair or replace the wiring harness, the relay, or the
fuse as required.
Is the repair complete?–System OK–