2004 DAEWOO LACETTI Ground

9B – 26ILIGHTING SYSTEMS
DAEWOO V–121 BL4
Backup Lamps Inoperative
StepActionValue(s)YesNo
11. Block the wheels.
2. Apply the parking brake to prevent the vehicle
from moving.
3. Turn the ignition on.
4. Put the transaxle in reverse (R).
5. Remove one of the backup lamps from its
socket.
6. Test the lamp socket positive terminal with a
voltmeter.
Does the battery voltage available at the backup
lamp socket positive terminal equal the specified
value?11–14 vGo to Step 3Go to Step 2
2Repair the open circuit between fuse F20 and the
backup lamps.
Is the repair complete?–System OK–
3Connect an ohmmeter between ground and the neg-
ative terminal at the bulb socket.
Is the resistance equal to the specified value?0 WGo to Step 4Go to Step 5
4Replace the faulty backup lamps.
Is the repair complete?–System OK–
51. Reinstall the backup lamps.
2. Disconnect the electrical connector at the re-
verse switch. (On automatic transaxle (A/T)
vehicles, disconnect the neutral safety/backup
switch.)
3. Turn the ignition on.
4. Put the transaxle in R.
5. Use a voltmeter to check for the reverse switch
terminal 1. (On A/T vehicles, test terminal 7 of
the neutral safety/backup switch).
Does the battery voltage available at terminal 1 (or
terminal 7, if equipped with A/T) equal the specified
value?11–14 vGo to Step 7Go to Step 6
6Repair the open circuit between the backup lamps
and the, reverse switch (or the neutral safety/backup
switch if equipped with A/T).
Is the repair complete?–System OK–
71. Put the transaxle in R.
2. Use an ohmmeter to check the continuity be-
tween reverse switch terminal 1 and terminal 2
(terminals 7 and 8 on the neutral safety/backup
switch, if equipped with A/T).
Does the continuity between terminals 1 and 2 (ter-
minals 7 and 8, if equipped with A/T) equal the speci-
fied value?0 WGo to Step 9Go to Step 8

LIGHTING SYSTEMS 9B – 27
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
8Replace the reverse switch (neutral safety/backup
switch, if equipped with A/T).
Is the repair complete?–System OK–
9Repair the ground circuit between the reverse switch
(neutral safety/backup switch, if equipped with A/T)
and ground G401.
Is the repair complete?–System OK–

9B – 28ILIGHTING SYSTEMS
DAEWOO V–121 BL4
Turn Signal Lamps and Hazard Lamps Do Not Work
StepActionValue(s)YesNo
1Check fuses F3 and F14.
Is either fuse blown?–Go to Step 2Go to Step 3
21. Check for a short circuit and repair it, if neces-
sary.
2. Replace the fuse.
Is the repair complete?–System OK–
31. Turn the ignition ON.
2. Check the voltage at fuses F3 and F14.
Does the battery voltage available at both fuses F3
and F14 equal the specified value?11–14 vGo to Step 4Go to Step 7
41. Turn the hazard switch on.
2. Remove each of the inoperative lamps from its
socket.
3. Test each lamp socket positive terminal with a
voltmeter.
Does the battery voltage pulsing at the turn signal
hazard lamp socket positive terminal equal the spe-
cified value?11–14 vGo to Step 5Go to Step 9
5At each bulb socket, use an ohmmeter to check the
ground circuit.
Is the resistance equal to the specified value?
0 WGo to Step 6Go to Step 8
6Replace any faulty turn signal/hazard bulbs.
Is the repair complete?–System OK–
7Repair the power supply circuit to fuses.
Is the repair complete?–System OK–
8Repair the open ground wires.
Is the repair complete?–System OK–
91. Turn on the hazard lamp switch.
2. Test the blinker unit connector terminal 49a
with a voltmeter.
Does the battery voltage pulsing at the blinker unit
terminal 49a equal the specified value?11–14 vGo to Step 15Go to Step 10
101. Turn on the hazard lamp switch.
2. Test the blinker unit connector terminal 49 with
a voltmeter.
Does the battery voltage available at the blinker unit
terminal 49 equal the specified value?11–14 vGo to Step 11Go to Step 14
111. Disconnect the blinker unit from the connector.
2. Use an ohmmeter to check between ground
and the connector for terminal 31 of the blinker
unit.
Is the resistance equal to the specified value?
0 WGo to Step 13Go to Step 12
12Repair the blinker unit ground connection.
Is the repair complete?–System OK–
13Replace the faulty blinker unit.
Is the repair complete?–System OK–

LIGHTING SYSTEMS 9B – 31
DAEWOO V–121 BL4
INTERIOR COURTESY AND LUGGAGE COMPARTMENT
LAMPS
Interior Courtesy Lamp Inoperative
CAUTION : Always make sure there is an electrical
load (lamp bulb, etc.) in any circuit between battery
terminals. Do not make a short circuit between bat-
tery terminals with a jumper wire. Hazardous spark-
ing would result and could cause injury.
Test Description
The number(s) below refer to step(s) on the diagnostictable.
1. Bulb test. Clip one end of a jumper wire to the neg-
ative battery terminal. Clip the other end of the
jumper wire onto one end of the bulb. Take the free
end of the bulb (the end without the jumper at-
tached) and touch it to the positive battery terminal.
Step
ActionValue(s)YesNo
11. Remove the interior courtesy lamp bulb and
inspect the filament.
2. If the filament is not broken, test the bulb using
the vehicle’s battery and a jumper wire.
Does the bulb pass the visual and physical checks?–Go to Step 3Go to Step 2
2Replace the bulb.
Is the repair complete?–System OK–
31. Reinstall the interior courtesy lamp bulb.
2. Check fuse Ef19.
Is fuse Ef19 blown?–Go to Step 4Go to Step 5
41. Check for a short circuit and repair it, if neces-
sary.
2. Replace the fuse.
Is the repair complete?–System OK–
5Check fuse Ef19.
Does the voltage at fuse Ef19 equal the specified
value?11–14 vGo to Step 7Go to Step 6
6Repair the open power supply circuit for fuse Ef19.
Is the repair complete?–System OK–
71. Disconnect the interior courtesy lamp electrical
connector.
2. Check the voltage at connector terminal 1.
Does the voltage at connector terminal 1 equal the
value specified?11–14 vGo to Step 8Go to Step 9
8Repair the open circuit between fuse Ef19 and the
interior courtesy lamp terminal 1.
Is the repair complete?–System OK–
91. With the interior courtesy lamp disconnected,
turn it to the on position.
2. Use an ohmmeter to check the resistance be-
tween ground and terminal 2 of the interior
courtesy lamp connector (harness side).
Is the resistance equal to the specified value?0WGo to Step 10Go to Step 11
10Replace the interior courtesy lamp switch assembly.
Is the repair complete?–System OK–
11Repair the ground circuit for the interior courtesy
lamp.
Is the repair complete?–System OK–

LIGHTING SYSTEMS 9B – 33
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
11Use an ohmmeter to check the resistance between
ground and the BLK wire at the luggage compart-
ment lamp switch connector (harness side).
Is the resistance equal to the specified value?0WGo to Step 12Go to Step 13
12Replace the luggage compartment lamp switch.
Is the repair complete?–System OK–
13Repair the ground circuit for the interior courtesy
lamp.
Is the repair complete?–System OK–

9B – 34ILIGHTING SYSTEMS
DAEWOO V–121 BL4
FOG LAMPS
Diagnostic Aids
The front fog lamps will not operate unless the illumination lamps or daytime running lamps are on. If the illumination lamps
or daytime running lamps are not operating, repair that problem before attempting to diagnose the fog lamps.
Front Fog Lamps Inoperative
StepActionValue(s)YesNo
1Check fuse Ef24.
Is fuse Ef24 blown?–Go to Step 2Go to Step 3
21. Check for a short circuit and repair it, if neces-
sary.
2. Replace the fuse.
Is the repair complete?–System OK–
3Use a voltmeter to check fuse Ef24.
Does the battery voltage available at fuse Ef24 equal
the specified value?11–14 vGo to Step 5Go to Step 4
4Repair the open circuit from the battery to fuse Ef24.
Is the repair complete?–System OK–
5Remove the fog lamp relay and temporarily substi-
tute a known good relay, such as the headlamp relay.
(Do not substitute the illumination lamp relay.)
Do the fog lamps work with the substituted relay?–Go to Step 6Go to Step 7
61. Return the substituted relay to its original posi-
tion.
2. Replace the inoperative fog lamp relay.
Is the repair complete?–System OK–
71. Return the substituted relay to its original posi-
tion, but do not reinstall the fog lamp relay.
2. Turn on the exterior lamps and the front fog
lamps.
3. Using a voltmeter, check the fog lamp relay
socket at the connector for fog lamp relay ter-
minal 30.
Does the voltage available at the fog lamp relay
socket equal the specified value?11–14 vGo to Step 9Go to Step 8
8Repair the open circuit between fuse Ef24 and the
fog lamp relay.
Is the repair complete?–System OK–
9At the fog lamp relay socket, use an ohmmeter to
verify that the connector for relay terminal 85 is con-
nected to ground.
Does the resistance equal the specified value?0 WGo to Step 11Go to Step 10
10Repair the ground circuit for the fog lamp relay.
Is the repair complete?–System OK–
111. Reinstall the fog lamp relay.
2. Turn ON the exterior lamps and the front fog
lamps.
3. Test for voltage at terminal 2 of the fog lamp
connector.
Does the battery voltage available at terminal 2 of
the fog lamp connector equal the specified value?11–14 vGo to Step 13Go to Step 12

LIGHTING SYSTEMS 9B – 35
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
12Repair the open circuit between the fog lamp relay
terminal 87 and the fog lamps.
Is the repair complete?–System OK–
13Use an ohmmeter (or test lamp) to check the ground
at terminal 1 of the fog lamp connector.
Does the resistance equal the specified value?0 WGo to Step 15Go to Step 14
14Repair the fog lamp ground circuit.
Is the repair complete?–System OK–
15Replace the faulty fog lamp bulbs.
Is the repair complete?–System OK–

9C – 4IHORN(S)
DAEWOO V–121 BL4
GENERAL DESCRIPTION
AND SYSTEM OPERATION
HORN(S)
The horns are located under the hood. They are attached
near the radiator at the front of the vehicle. The horns are
actuated by pressing the steering wheel pad, which
grounds the horns’ electrical circuit.