2003 HONDA CIVIC under-dash

Heating and Air Conditioning
Air Mix Control Motor Test
1. Disconnect the 5P connector from the air mix
control motor.
2. Connect battery powertothe No. l terminal ofthe
air mix control motor, and ground the No. 2
terminal; the air mix control motor should run, and
stop at Max Cool. lf it doesn't, reverse the
connections;the air mix control motor should run,
and stop at Max Hot. lf the air mix control motor
does not run, remove it. then check the air mix
control linkage and door for smooth movement.
. lf the linkage and door move smoothly, replace
the air mix control motor.. lf the linkage ordoorstickor bind, repairthem as
needed.. lf the air mix control motor runs smoothly, go to
step 3.
AIR MIX CONTROL MOTOR
3.
4.
Measure the resistance between the No. 4 and
No. 5 terminals. lt should be between 2.1 k to
3.9 kQ.
Reconnect the air mix control motor 5P connector,
then turn the ignition switch ON {ll).
Using the Backprobe Set, measure the voltage
between the No. 3 and No. 4 terminals.
Max Cool about 1V
Max Hot about 4 V
lf either the resistance or voltage readings are not
as specified, replace the air mix cotrol motor.
21-34
Air Mix Control Motor Replacement
1.Remove the under-dash fuse/relay box (see page
22-491.
Disconnect the 5P connector {A) from the air mix
control motor (B). Remove the self-tapping screws
and the air mix control motor from the heater unit.
Remove the rod (C) from the arm (D) of the air mix
controi motor.
Install the motor in the reverse order of removal.
After installation, make sure the motor runs
smoothly.
3.
\'
,.,:l'

Evaporator Temperature Sensor
Replacement
1.Remove the driver's dashboard lower cover (see
page 20-59) and the under cover (see page 20-60).
Remove the under-dash fuse/relay box (see page
22-491.
Disconnect the 2P connector (A) from the
evaporator temperature sensor (B), then remove
the connector clip (C). Remove the self-tapping
screw, and carefully pull out the evaporator
temperature.
4. Install the sensor in the reverse order of removal,
Evaporator Temperature Sensor
Test
l. Dip the sensor in ice water, and measure the
resistance between its terminals
EVAPORATOR TEMPERATURE SENSOR
2.
3.
Terminal side ol male terminals
Then pour hot water on the sensor, and check {or a
change in resistance.
Compare the resistance readings with the
specifications shown in the graph; the resistance
should be within the specifications
RESISTANCEk9
t0
32050 68 86 'F
10 20 30'c
TEMPERATURE
21-37

\Body Electrical
Body ElectricalSpecialToolsGeneral Troubleshooting tntorrnaiion.'......
Relay and Control Unit Locations .....
Connectors and Harnesses
Fuse/Relay Boxes ...............................
Power Distribution .............................
Ground Distribution ...........................
Under-dash Fuse/Relay Box ..............
Battery ..............
Relays ................
*lgnition Switch ..............
*Gauges
Component Location Index .......................Self-diagnostic Procedure ..........................Circuit DiagramGauge Bulb Replacement ..........................Gauge Assembly ReplacementCoolant Temperature
Gauge Troubleshooting .... ....................Vehicle Speed Signal CircuitTroubleshootingVSS Replacement
Exterior LightsComponent Location Index .......................Circuit DiagramDaytime Running Lights ControiUnit Input Test (Canada) ........................Headlight Ad,ustment .................. .. .....Headlighr Replacement ..............................Combination Light SwitchTest/ReplacementBulb ReplacementTaillight Replacement ..........................High Mount Brake Light Replacement ......License Plate Light Replacement ..............Side Marker Light Replacement ................Brake Pedal Position Switch Test ..............Side Turn Signal Light Replacement ........
Turn Signal/HazardFlasher SystemComponent Location Index .......................Circuit DiagramTurn Signal/Hazard Relay lnputTest ........Hazard Warning Switch Test
22,3
22-7
22-13
22-44
22-46
22-4A
22-49
22-50
22-51
22-53
22-5422-5622-5422 6322-64
22-64
22-6522 61
22-6822--71
22-7 622-7422-79
22-AO22-4122-8222-4222-4322-4322-4422-84
22-8522 A622-8722-88
22-10422-105
22-10622-107
Entry Lights control systemComponent Location Index ....................... 22-89Circuit Diagram ......... 22 90lgnition Key Switch Test .....................,...... 22-9'llgnition Key Light Test ............................... 22-91Control Unit Input Test ..........,.................... 22 92
Interior LightsComponent Location Index ....................... 22-94Circuit Diagram ......... 22-95Ceiling LighVSpotlightsTesVReplacement ................................... 22-96Rear Ceiling Light TesVReplacem ent ........ 22-96Cargo Area Light Test/Replacem ent ......... 22-97Hatch Latch Switch Test ..,..,....................... 22-97
*Audio SystemComponent Location Index ....................... 22-98Circuit Diagram ......... 22,99Audio Unit Removal/lnstallation ............... 22-1OOAudio Unit Connector Replacement ......... 22-101Speaker Replacement ................................ 22-102Roof Antenna Rep1acement ....................-.. 22-103
Rear Window DefoggerComponent Location Index ...........Circuit Diasram .. ....... .. ..... ....... ...:::::.::.::.Function TestDefogger Wire Repair .................................Noise Condenser CapacityTest ................
MoonroofComponent Location Index ....................... 22-1OBCircuit Diagram ......... 22-109Moonroof Control Unit Input Test ............. 22-'l10Switch TesVReplacement ........,.....,........... 22-1 12Motor Test ................. 22-112Limit Swilch Test ...... 22-'l'13Auto-stop Switch Test ................................ 22-1 13
Power MirrorsComponent Location Index ....................... 22-114Circuit Diagram ......... 22-115Function Test ............. 22-116Power Mirror Switch Test .......................... 22-ll7Power Mirror Actuator Test ....................... 22-117Power Mirror Actuator Replacement ........ 22-11A
* HornsComponent Location Index ....................... 22-120Circuit Diagram ......... 22-121Horn TesVReplacement ...........................-. 22-122Horn Switch Test .,.... 22-122
\

Connectors and Harnesses
Connector to Harness Index (cont'd)
Engine Compartment Wire Harness (Dashboard)lcont'dl
Connector or TerminalCavitiesLocationConnectstoNotesFog light connectorUnder'dash fuse/relay boxconnector F (see page 22-45)Underdash fuse/relay boxconnector G (see page 22-45)Underdash fuse/relay boxconnector H (see page 22'45)Under-dash fuse/relay boxconnector | (see page 22'45)Under-dash fuse/relay boxconnector J (see page 22-45)c 151
c401
c451
c452
c501
c502
c502
c503
c851'14
2
3
1
I
9
6
6
5
5
12
10
112
10
3
5
8
2
'10
4
8
5
10
1
Under maddle of dashUnder left side of dash
Under left side of dash
Under left side of dash
Under left side of dash
Under left side ol dash
Under right side of dash
Under right side ot dash
Under right side ot dash
Under right side oJ dash
Under right side oI dash
Under right side ol dash
Under right side oJ dash
Under right side oJ dash
Under middle of dash
Under right side of dash
EPS subharness {see page 22-24)Dashboard wire harness B(see page 22-30)ECM wire harness (see page22-321ECM wire harness (seo page22 32)Dashboard wire harness A(see page 22-26)Dashboard wire harness Alsee page 22-261Dashboard wire harness A(see page 22-26)Dashboard wire harness A(see page 22-26)Floorwire harness (see page22-34l',VC wire harness lsee page22-43\
Oplion
Canada
USA
G4021'IEody ground via engine..mdarlma.t w,rc harncss
22-22

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UNDER-DASH FUSE/RELAY BOX
ENGINE COMPARTMENT WIRE
22-23

Connectors and Harnesses
Dashboard Wire Harness A {Left branchl
Connector or TerminalffiAccessory power socketAudio antennaBrake pedal position switchClutch interlock switchClutch pedal poistion switchCruise control unitCruise main switchDaytime r!nning lights control unitDaytime running lights relayGauge assembly connector AGauge assembly connector BHazard warning switchHeater control panel connector AHeater control panel connector BHVAC push switch assemblyKeyless receiver unitLow beam cut relayOptional security connectorPower mirror switchUnder-dash fuse/relay boxconnector K (see page 22-45)Under'dash fuse/relay box
L {see page 22-45}Underdash fuse/relay boxconnector M lsee page 22'45)Under-dash fuse/relay boxconnector N (see page 22-45)UndeFdash fuse/relay boxconnector O (see page 22-45)UndeFdash fuse/relay boxconnectorY (see page 22 45)c504
c505
c506
c507
c508
c509
c510
22226
3029628
I820111819105327
,I4
12
11
34
1
24
25
2 Under middle of dash2 Under left side of dash4 ] Under left side of dash2 ] Under left srde of dash2 | Under left side of dash14 I Under left side of dash5 Under left side of dash14 Under lett side of dash4 Under lett side of dash22 I Behind gauge assembly22 i Behind gauge assembly10 Behind hazard warnning switch22 Behind heater control panel'14 Behind heater control panel10 ] Behind HVAC switch assembly5 I Under middle of dash5 lUnderleftsideofdash16 Under lefr side of dash13 Under left side oI dash17 ln the under-dash fuse/relay box
CanadaCanada
l0In the under-dash fuse/relay box
In the undeFdash fuse/relay box
In the underdash fuse/relay box
In the under-dash fuse/relay box
In the under-dash fuse/relay box
Under left side of dash
Under left side ot dash
Under left side of dash
Under left side of dash
Under middle of dash
Under middle of dash
Under middle ol dash
Driver's door wire harness(see page 22'40)Driver's door wire harness(see page 22-40)Left side turo signal lightsuonarnessRoof wire harness (see page22 3AlFloor wire harness {see page22-341Floor wire harness (see page22 34JDashboard wire harness B(see oaoe 22-30)
12
12
G501
G503
1
21
Under gauge assembly
Under left side of dash
Body ground via dashboard
Body ground via dashboard
Left Side Turn Signal Light Sub harness
Connector to Harness Index (cont'd)
L
Connector or TerminalCavitiesLocationConnects toNolesLeft side turn signal lightc506353422Behind left side turn signal lightUnder left side of dashDashboard wire harness A
22-26

Connectors and Harnesses
Connector to Harness Index (cont'd)
Dashboard Wire Harness B
Collqctor or TerminalCavitiesLocatiol|ConnectstoNotesCableCombination light switchDriver's airbag inflatorlgnition key switchlgnition switchlmmobilizer control unit receiverPassenger's airbag inf latorSRS unit connector AWiper/washer switchUnder dash fuse/relay boxconnectorA lsee page 22,45)Under dash luse/relay boxconnector B (see page 22-45)Under'dash fuse/relay boxconnector C (see page 22-45)Under-dash fuse/relay boxconnector S lsee page 22-45)Under'dash fuse/relay boxconnectorX (see page 22 45)c401
c402
c403
G510
reel211716't9
18I
35
6
1
8
10
12
11
14
5
4
11418145
6
14
2
8
10
4
12
In steering column coverIn steering column coverIn steering column coverIn steering column coverIn steering column coverIn steering column coverUnder middle of dashUnder middle ofdashIn steering column coverUnder left side of dash
Under left side ofdash
Under left side of dash
Under lett side of dash
Under left side of dash
Under right side of dash
Under middle of dash
Under middle of dash
Under middle side of dash
Engine compartment wireharness (see page 22-'18)Floor wire harness (see page22-34JFloor wire harness (see page22-341Dashboard wire harness A(see oaoe 22-26)G40lUnder gauge assemblyBody ground via dashboard
22-30

Connectors and Harnesses
Connector to Harness Index (cont'd)
ECM Wire Harness
Connector or TerminiFI Re-lcavitiesL LocationConnectstoNotesArr ruer t/vrl ralo sensor retayData link connectorEC[/l connector EPGM-Fl main relay 1PGM-Fl main relay 2Under-dash fuse/relay boxconnector D (see page 22 45)Underdash fuse/relay boxconnector E lsee page 22-45)under-dash fuse/relay boxconnector R lsee page 22-45)c10'1
c152
c451
c452
c453
c511
8761
2
3
4
1'I
I
10
14
12
44
6
20
8
4
6
Eehind glove boxUnder middle of dashBehind glove boxBehind glove boxBehind glove boxIn the under-dash fuse/relay box
In the under-dash fuse/relay box
In the under-dash fuse/relay box
Under rlght side of dash
Under right side of dash
Under right side of dash
Under right side ot dash
Under middle oI dash
Under middle of dash
Engine wire harness (seepage 22'16)EPS sub harness (see page22-24)Engine companment wireharness {see page 22-18)Engine compartment wireharness {see page 22-18)Floor wire harness (see page22-34)Dashboard wire harness A{see oaoe 22-26)G451Under gauge assemblyBody ground via ECM wireharness
22-32