1997 HONDA CIVIC Horn relay

ldle Control System
Brake Switch Signal ('96 - 98 Models, '99 - 00 Dl6YS engine with M/Tl
This signals the ECM/PCM when the brake pedal is deoressed.
LGlBKSW(GRN/WHTI
D {16P)
Wire side of female t€rminals
Inspection of Brake Switch Signal.
Are the brake lights on withoutdepressing the brake pedal?
Depress the brake pedal.
Inspect the HORN (15 A) fuse inthe under-hood fuse/ relay box.Do the brake lights come on?
- Repair short in the wirebetween the brake 3whch andrhe HORN 115 At lu3e.- Replace the I|oRN 17.5 A) tus€.
Repair open in the wirebetween the brake switch andthe HORN 115 Al fuse.Inspect th6 br.ke switch {s6€section l9l.Check tor an open in the wireIBKSW line):1. Oepress the brake pedal.2. Measure voltage betweenECM/PCNI connector terminalsAg and D5 with the brake pedaloepresseo.
Repair open in the wire b€tweenthe ECM/PCM {Dsl and the brakeswitch.
ls there battery voltage?
Brakc switch sign.l is OK.
ECM/PCM CONNECTOFS
A (32PtIBRI\v
,la678101112I
121311151617t8192022232aI9101112
25212Aa3013141516
11-210

IJBrake Switch Signal ('99 - 00 Models except Dl6Y5 engine with M/Tl
This signals the ECM/PCM when the brake pedal is depressed
I
lnsoection ot Brake Switch signal.
Are the brake lights on without
depressing the brake Pedal?
Depress the brake Pedal
Inspect the HoRN {15 A} fuse in
the underhood fuse/ relay box'Do the brake lights come on?
- R.pair short in the wiro be'
tween the brake switch and
the HORN (15 Alfuse.- Replac€ the HORN (15 A) tuse.
- Repair open in the wite be'
tween the brako switch and
the HORN (15 Alfuse.- lnsoect the brake switch (3ec
section tgl.
Check fot an oPen in the wire
{BKsw linel:
1. Depress the brake Pedal.2. Measure vohage beween ECM/
PCM connector terminals A32
and 820 with the brake Pedaldepressed.
Bepair open in the wire between
the ECM/PCM (A32) and the
brake switch.
Brake switch signal i5 OK
ECM/PCM CONNECTORS
BKSW (GRN/WHTI
LG1 {BRN/BLK)
Wire side o{ female terminals

Component Locations
ta
SERVICE CHECK CONNECTOR {2PIBIGHT.REAR WHEELSENSOR CONNECTORMOOULATOR UNITABS CONTROL UNIT
RIGHT-REAR WHEEL SENSOR
LEFT.R€AR WHEELSENSOR CONNECTOR
J
UNDER.DASH FUSE/RELAY 8OX
LEFT.FRONT WHEEL SENSOR
ABS +B (20 A) FUSE
UNDER.HOOD FUSE/RELAY BOX
lcl lilo Al FUSE
ABS INDICATOR LIGHT
UNOEF.DASI{ FUSE/RELAY BOX
HORN/STOP I15 A) FUSE
UNDER.HOOO ABS FUSE/RELAY BOX
PUMP MOTOR {'O A} FUSE
PUMP MOTOR BELAY
E
o
METEB I7.5 AI FUSE
0
0
0
00000 n
00000 u
BR DEF RLY 17,5 A) FUSE
t
MTR CHECK (7.5 AI FUSE
19-45

l'f .
Electrical
Special Toofs .,....................,23-2
Troubleshooting
Tips and Precautions ..............,.................... . 23-3
Five-step Troubleshooting .............. ......... . . 23-5
wire color codes ..........,23-5
Schematic Symbols ........,................... . . .. .... 23-6
Relay and Control Unit Locations
Engine Compartment ...,..................... ... .. . 23'7
Dashboard ......................23-8
Dashboard/Door ......... 23-12*Airbags ................. ....... Section 24
Air Conditioning ......... Section 21
Aftelnator ..........."""" """ 23-112
Anti-lock Brake System {ABS) Section 19*A/T Gear Position Indicator .....................,. .... ... 23-149
Automatic Transmission Svstem .... . ....... Section 14
Batterv ......... . . . ... ...... .......23-91
Blower controls .. . ... Section 2l
Charging System ....'...........23'112
Connector ldentilication and Wire Harness
Routing .................. ......23'13
Cruise Control ............,........23-240
Dash Lights Brightness Controller ............. ....... 23-180
Fan controfs "" 23'126
Fuel PumD ........ . ........ section 11
Fuses/Refay ...............,..,,.. 23'62
PGM-FI Control System ......................,....... Section 1 1
*Gauges
Circuit Diagram ....,.,.......23-131
Fuef Gauge ...........'.'.......23-142
Gauge/lndicator .. . .. 23-129
Ground Distribution .. . 23-75
Heatei controls .. . ..... Section 21*Horn................. ...............23-196
*tgnition Switch ....................23-89
lgnition System .......,.... 23-102
*lntegrated Control Unit ....................................... 23-156
fnterlock System ,........ . . , ,23-144
Lighting System . . . .. ......... 23-161
Lights, Exterior
Back-up Lights ..'............23'171
Brake Lights .................. 23'174
Daytime Bunning Lights (Canadal ............... 23'166
Front Parking Lights ......,................ .'. .......... 23-167
Front Turn Signal Lights .......... . . ............ ..,.23-167
Headtights ....".'....-... ..... 23'167
High Mount Brake Light ...................... ... .23'179
License Plate Lights ...... 23'176
Taitfights ................ .......23'171
lnterior Lights ..-.......,, . 23-142
Moonroof ..,.................,........ 23-235
Power Distribution ....... . . .23-61
Power Door Locks .......,,,. .23'251
Power Mirrors ,..............,.,...23'206
Power Relays ....... . ...... . . .. 23-86
Power Windows ............,,....23-220
Rear Window Defogger .......................... . . ... . . 23-2OO
Spark Plugs . ..... . ........ .....23-111
Slarting System ................23-93*stereo Sound Svstem ,................. ..... ... . ... ,.,.,,23'147'Supplemental Restraint System (SRS) ... . Section 24
Turn Signal/Hazard Flasher System .......'.'....-... 23-173
*Undel-dash Fuse/Relay Box ............,.................. 23-85
vehicfe soeed sensor (VSSI """" ""' 23-140+Wipers/Washers .........,.,.,...23-214
NOTE: Unless otherwise specified, references to auto-
matic transmission (Mf) in this section include the CVT.

Troubleshooting
Schematic Symbols
BATTERY
E
@
GROGroLrnd terminal
II_d:
UNDComponent ground
II_..'-
FUSE
--cn-.e
COIL, SOLENOID
r{r
tql'|
CIGARETTE LIGHTER
A
lrl
P
RESISTOR
I
f
VARIAELE RESISTOR
ilH
THERMISTOR
c
IGNITION SWITCH
-fo o.t-
BULB
+
HEATEB
At-l
F
MOTOR
0
PUMP
H
CIRCUIT BREAKER
I
r
Yr
T
HORN
+
DIODE
+
SPEAKER, BUZZER
D
Mast
Y
ANTt:f\,NATRANSISTOR lTrl
II
SWITCH (ln niNormally open
I
/F\t tL I\Y/
I
rrdal positionlNormally closed'*i."n
@
I
LIGHT EMITTINGDIODE ILEDI
A+,
TT
RELAY lln noNormally opon relay
| ....--1'rl*r
til
t "t^f
fmal poaitionlNormally closed relay
ffl-+- |
lrl
lrl
fff
CONDENSER
I
T
CONNTInput
V
I
:CTIONOutput
J
CONNECTOR
*>-
'l!
REED SWITCH
A
tftl
Y

D
INTEGRATEDCONTROL UNITUNDER.OASHFUSE/RELAY BOX
HORN RELAYI Wire colors: WHT/GRttt, WXf/Cnru,l
[GRY, and BLU/RED ,J
POWER WINDOW RELAY
INTERLOCK CONTROL UNIT
'gtP"tat{}r) (}t /t t ------,)
F;;snHn-nnn"nf-H-n o
F !r rr rr rr r,r Lr Ll u u l,r
Fnnnnnnnrrrr-1F rr rr rJ LJ rJ r-r t-r L-r LJ Lr ||J
u_::;_:_:_:_:_l_;I::
*TCM (CVT)
*: Coupe
23-9

Connector ldentification and Wire Harness Routing
Connector or
Terminal
Number of
CavhiosLocationConnocts ioNotes
c401
c402
c403
c404
c405
c406
c407
c407
c408
c409
c410
c411
c412
c413
c414
c415
c416
c417
c418
c4l9
c420
c42'l
c423
c424
c425
c426
c427
c42A
c429
c430
c431
c432
c433
c434
c435
c431
c438
c439
'14
't4
I
I
10't2
24
16
7
o
18
20
18
7
6
I
o
4
7
8
14
1
Above under-dash fuss/relay box
Under left side ot dash
Under left sid€ of dash
Under left side of dash
Under left side of dash
Und€r left side of dash
Under left side of dash
Under left side of dash
Under left side of dash
Behind under-dash fuse/relay box
Under left side of dash
Under left side of dash
Above under-dash fuse/relay box
Under left side of dash
Under left side of dash
Above under-dash fuse/r€lay box
Under left side of dash
Under left side of dash
Under left side of dash
Behind under-dash fuse/relay box
Eehind under-dash fuse/relay box
Behind under-dash fuse/relay box
Behind under-dash fuse/relay box
Behind under-dash fuse/relay box
Under left side of dash
Under left side of dash
In the steering column cover
In the steering column cover
In the steering column cover
In the steering column covEr
Under left side of dash
Under left side of dash
Under middle of dash
Under middle of dash
Under middle of dash
Under middle of dash
Under left side of dash
Under left side of dash
Eehind under-dash fus€/relay box
Floo. wire harness (C555)
Floor wire harness (C554)
Security system
Cruise control unit
Daytime running lights control unit
Daytime running lights control unit
Roof wire harness (C701)
Moonroof wire harness (C7l1)
Front fog light connector
Integrated control unit
Dashboard wire harness (C504)
Dashboard wire harness (C502)
SRS main harness (C802)
Data link connector
Starter cut relay
lgnition switch
Security system
Clutch switch
Clutch interlock switch
Under-dash fuss/relay box (C9191
Undor-dash fuse/r€lay box {C920)
Under-dash tuse/relay box (C922)
Under-dash luse/relay box (C914)
Under-dash fuse/rBlay box (C915)
Horn relay
Brake swilch
Windshield wiper/washer switch
Rear window wiper/washer switch
Turn signal switch
Combination lighvturn signal switch
Cable reel
lnterlock control unit
Secondary heated oxygen sensor sub-
harn€ss (C781)
Ay'T gear position switch
Shift lock solenoid
Park pin switch and Ay'T gear position
console light
Transmission control module (TCM)
Transmission control module {TCM)
Under-dash fuse/relay box {C925)
ABS
Optional
Canada
Canada
Optional
Atr
MTT
Optional
Mlf
NT
Atf
CVT
CVT
Optional
AN
Atr
G401Left kick panelBody ground, via main wire harness
Main Wir€ Harness (Loft side of da3h and floor branch): '96 - 97 models
*2:Without moonroof*4: With moonroof*5: M/T (with cruise control or for D16Y5 engine)*6: With secondary heated oxygen sensor (H02S)
23-32

Connector ldentification and Wire Harness Routing
Connoctor or
Tgrminal
Number of
CavitiesLocationConneqts toNot€s
c401
c402
c403
c404
c405
c406
c407
c407
c408
c409
c410
c411
c4't2
c413
c414
c415
c416
c417
c418
c419
c420
c421
c422
c423
c424
c425
c426
c427
c428
c429
c430
c431
c432
c433
c434
c435
c437
c438
't4
l4
8,
1
10
12
24
7
6
18
20
18
7
6
8
7
8
14
2
Above under-dash fuse/relay box
Under left side of dash
Under left side of dash
Under left side of dash
Under left side of dash
Under left side of dash
Under left side of dash
Under left side of dash
Under left side of dash
Behind under-dash fuss/relay box
Under left side of dash
Under left side of dash
Above under-dash fuse/relay box
Under left side of dash
Under-dash relay box
Above under-dash fuse/relay box
Under left side of dash
Under left side of dash
Under left side of dash
Eehind under-dash fuse/relay box
Behind under-dash fuse/relay box
Behind under-dash fuse/relay box
Behind under-dash fuse/rslay box
Behind under-dash fuse/relay box
Under-dash relay box
Under left side of dash
In the steering column cover
In the steering column cover
In the steering column cover
In the steering column cover
Under left side of dash
Under left side of dash
Under middle of dash
Under middle of dash
Under middle of dash
Under middle of dash
Under left side of dash
Under left side of dash
Floor wire harness (C555)
Floor wire harness (C554)
Security system
Cruise control unit
Daytime running lights control unit
Daytime running lights control unit
Roof wiro harness (C7011
Moonroof wire harness (C711)
Front fog light connector
Integrated control unit
Dashboard wire harness (C504)
Dashboard wire harness (C502)
SRS main harness (C802)
Data link connector
Starter cut relay
lgnition switch
Security system
Clutch switch
Clutch inlerlock switch
Under-dash fuse/relay box (C919)
Under-dash fuse/relay box (C920)
Under-dash fuse/relay box (C922)
Under-dash fuse/relay box (C914)
Under-dash fuse/relay box (C915)
Horn relay
Brake switch
Windshield wiper/washer switch
Rear window wiper/washer switch
Turn signal switch
Combination light/,turn signal switch
Cable reel
lnterlock control unit
Secondary heated orygen sensor sub-
harness (C781)
Ay'T gear position switch
Shift lock solenoid
Park pin switch and Aff gear position
console light
Transmission control module (TCMI
Transmission control module (TCM)
ABS
Optional
Canada
Canada
Optional
M
MIT
Optionsl
MlT
Alr
NT
NT
CVT
CVT
G401Left kick panelBody ground, via main wire harness
Main Wire Harn€ss {Left side ot dash and floor branchl: '98 model
*2: Without moonroof*4:With moonroof*5: M/T (with cruise control or for D16Y5 engine)*6: With secondary heated oxygen sensor (H02S)
23-34