2000 HONDA CIVIC Light switch

Ground Distribution Schematics
This sample Ground Distribution schematic shows all of the components that share two
ground points.
TCSCONTROLUNITPage 35
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FRONTPASSENGER'SSEAT HEATERPage 147
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FRONTPASSENGER'SSEAT BELTSWITCHPage 145
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RIGHTREAR DOORASHTRAYLIGHTPage 114
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Five-Step Troubleshooting
L Verify The Complaint
Turn on all the components in the problem
circuil lo check the accuracy of the customer
complaint. Note the symptoms. Do not begin
disassembly or testing until you have
narrowed down the problem area.
2. Analyze The Schematic
Look up the schematic for the problem
circuit. Determine how the circuit is
supposed to work by tracing the current
paths lrom the power source through the
circuit components to ground. Also, trace
circuits that share wiring with the problem
circuit. The names of circuits that share the
same fuse, ground, or switch, and so on, are
referred to in each circuit schematic. Try to
operate any shared circuits you didn't check
in step 1 . lt the shared circuits work, the
shared wiring is OK, and the cause must be
in the wiring used only by the problem
circuit. lf several circuits fail at the same
time, the fuse or ground is a likely cause.
Based on the symptoms and your
understanding of the circuit's operation,
identify one or more possible causes.
3. lsolate The Problem By Testing The Circuit
Make circuit tests to check the diagnosis
you made in step 2. Keep in mind that a
logical, simple procedure is the key to
efficient troubleshooting. Test for the most
likely cause of failure first. Try to make tests
at points that are easily accessible.
4. Fix The Problem
Once the specific problem is identified,
make the repair. Be sure to use proper tools
and safe procedures.
5. Make Sure The Circuit Works
Turn on all components in the repaired
circuit in all modes to make sure you've
fixed the entire problem. ll the problem was
a blown fuse, be sure to test all of the
circuits on that fuse. Make sure no new
problems turn up and the original problem
does not recur.
Test Equipment
Most circuits include solid-state devices.
Test the voltages in these circuits only with
a 1o-megaohm or higher impedance digital
mUltimeter. Never use a test light or analog
meter on circuits that contain solid-state
devices. Damage to the devices may result.
Test Light and DVOM
On circuits without solid-state devices, use a
test light to check for voltage. A test light is
made up of a 12 volt bulb with a pair of leads
attached. After grounding one lead, touch the
other lead to various points along the circuit
where voltage should be present. The bulb
will go on if there is voltage at the point being
tested. lf you need to know how much
voltage is present, use a digital
volVohmmeter (DVOM).
Self-Powered Test Light and DVOM
Use a self-powered test light to check for
continuity. This tool is made up of a light bulb,
battery, and tlvo leads. To test it, touch the
leads together: the light should go on.
Use a self-powered test light only on an
unoowered circuit. First, disconnect the
battery, or remove the fuse that feeds the
circuit you are working on. Select two points
in the circuit belween which you want to
check continuity. Connecl one lead of the
self-powered test light to each point. lf there
is continuity, the test light's circuit will be
completed, and the light will go on.
SELF-POWERED TEST LIGHT
lf, in addition, you need lo know exacW hc'.
much resistance there is between two oo'^=
use a digital volUohmmeter (DVOM)
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How To Use This Manual
Troubleshooting Tests
Testing for Voltage Drop
Wires, connectors, and switches are designed
to conduct current wilh a minimum loss of
voltage. A voltage drop of more than one volt
indicates a Droblem.
'1. Place the digital volVohmmeter (DVOM) in
the appropriate DC volts range. Connect
the positive lead to the end of the wire
(or to the connector or switch) closest to
the bafterv.
Connect the negative lead to the other
end of the wire (or the other side of the
connector or switch).
Turn on the components in the circuit.
The DVOM will show the difference
in voltage between the two points. A
difference, or drop, of more than one
volt indicates a oroblem. Check the
circuit for loose, dirty, or bent terminals.
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Testing lor a Short with a Test Light or DVOM
1. Remove the blown fuse and disconnect
the load.
2. Connect a test light or digital
oltr'ohmmeter
(DVOM), switched to the appropnare DC
volts range, across the tuse lerminals to
make sure voltage is present. You might
have to turn the ignition switch to ON:
check the schematic to see.
<-s80RT TOGFOUNO
Disconnecl lheload here.
Beginning near the luse box, wiggle the
harness. Continue this at convenient ooints
about six inches apart while watching the
test light or DVOM.
Where the test light goes off, or the DVOM
voltage drops to zero, there is a short to
ground in the wiring near that point.
NOTE: Always use a DVOM on high
impedance circuits. A test light may not
glow (even with battery voltage present).
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.t.
TEST LIGHTolDVOM

Testing for a Short with a Sell-Powered
Test Light or DVOM
1. Remove the blown fuse and disconnect
the battery and load.
2. Connect one lead of a self-powered test
light or digital volUohmmeter (DVOM)
(switched to the lowest "OHMS" range) to
the fuse terminal on the load side.
Dlsconnect the batlery.
FUSEBOXRemove the fuse.
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Dlsconnect theload here.
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Connect the other lead to a known
good ground.
Beginning near the fuse box, wiggle the
harness. Continue this at convenient
points about six inches apart while
watching the test light or DVOM.
lf the self-powered test light goes on or
the DVOM displays a low reading or no
reading (zero), there is a short to ground
in the wiring near that Point.
SELF.POWEREDTEST LIGHTo1DVOM
4.
5.
Testing tor a Short with a Short Circuit
Locator (Short Finder)
1 . Remove the blown fuse. Leave the
battery connected.
2. Connect the short finder across the battery
terminals and the load (component) side of
the fuse terminal.
SATTERY
SHORTFINOER
FUSEBOX
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3. Close all switches in the circuil
you're testing. (co,f,O
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Fuse/Relay Information
- Under-dash Fuse/Relay Box
Front View
c712(To moonroof wire harness)
. : Canadai : Not UsedO : C926 loprion (+B)l
@ : C927 loption (dash lights)]
O : C928 [Option (ACC]I
@ : C929 loption (lc2)l
Rear View
css2
c421(To main wire harness)
c801CI-o SRS main harness)
c501(To dashboard wire harness)
^ : Not used ('96-'97 models)
c913(To ignition switch)
INTEGRATEDCONTROL UNITCONNECTOR A
c419Oo main wire harness)
REAR WINDOWDEFOGGER RELAY
TURN SIGNAUHAZARD RELAY
c423(To main wire harness)
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c422(To main wire harness)
POWERwtNDowRELAY
c551flo lloor wire harness)c439 f96.'97 MODELSand ALL GX MOOELS)(To main wire harness)
T1 T-t T"l T"t r-r r-'l T1 F n r-l r-l r'123 24 25 26 27 28 29 30 31 32 33I-J I.J I.J IJ IJ IJ LJ IJ IJ I.J I.J I-I
r"1 r-t r-t T-l r"l r-r Fl r:1 n rJ n -12 13 14 t5 16 17 t8 19 2A 2t 22LI I.J L! LI tJ LJ (J LI IJ IJ T-I I.J
n r:l rj.l |-l T"l Tl r:t n r-l |;.l r-r r-l1 2 3 4 5 6 7 I 9 10 11LI LI IJ LJ LJ I,J T-I I.J TJ IJ I.-I tJ
c420(To main wire harness)
6
(To floor wire harness)

Fuse
NumberAmpsPageFuse Name
(RR WIPER
RR WASHER)
i R HiL HIGH BEAM | 10
L H/L HIGH BEAM
| (PAIV RR-L)
i (P/vv RR-R)
(rGN CO|L)
10I (P,^/V AS)
Component or Circuit Protected
Not used
Not used
Rear wiper, Security system (option)
(Vehicles pre-wired for accessory security system)
'10r 1n-2
I
| 1 10-12i Right headlight, DRL control unit (Canada)
Lett headlight, DRL control unit (Canada)
I ro-rsSecurity system (option)
| 120-2 | Left rear window motor
Right rear window motor
lgnition coil ('98-'00 models except GX)
| 120-1 | Front passenger's window motor
i (PiW DH)| 20 1 12O I Driver's window motor
TURN LIGHTSHazard warning switch
FUEL PUMP
(SRS UNIT)
PGM-FI main relav, SRS unit
(cRUrsE CoNTROL)
/KtrVt trSS\
Stereo radio tuner ('96-'98 USA: LX, EX, and HX),
Cruise control main switch, Keyless door lock
control unit ('99-'00 models with keyless entry)
15ALTERNATOR
SP SENSOR
l-a10-4I ELD unit, Gauge assembly, TCM (96-'98 CW, PGM-FI
16I RR DEF RELAY7.510-8I Rear window defogger ('96-'98 models), ABS control
I unit. Power mirror switch ('99-'00 models except GX)
i-HEATER r/C
I RELAY
Power mirrors ('96-98 models and all GX models),
Air delivery, Blower controls, AilC compressor
controls, Fans
I (RUNNING LIGHT
I RELAY)
1 7.5 1
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I DRL control unit (Canada)
i BACK-UP LTGHTSi Back-up lights
(RUNNING LIGHT)DRL control unit (Canada)
I R H/L LOW BEAM'10 l11o-12Right headlight
I L H/L LOW BEAM | 101110-12 | Left headlight
(cont'd)
(SRS)SRS unit
6-1

Fuse
NumberFuse NameAmpsPage
BATTERY
Component or Circult Protected
Power distribution
lgnition switch
INTERIOR LIGHT | 7.5 | 10-10 | DLC, Ceiling light, Trunk light
FI E/M15 i(20 GX) i
i PGM-FI main relay, Fuel injection relay (GX)
Not used
POWER WINDOW| 10-10 | Power window relay
BACK UPStereo radio iuner ('9G'98 mod€ls), Audio unit ('99100
models), Heater control panel, PCM/ECM, TCM (9e'98
cvr)
HEADLIGHT
REAR DEFROSTER I
DOOR LOCK UNIT,
ROOF
i 10-12i Headlights
Not used
Rear window defogger relay
Power door lock control unit (all except '99-'00 models
with keyless), Keyless door lock control unit ('99-'00
models with keyless), Moonroof
i HORN, SrOP Lri 10-13i Horn relay, Brake switch
HAZARDHazard warning switch
OPTIONI 10-13I Security system (option)
i HEATER MOTOR Ii 10-1 i Blower motor relay
(CONDENSER FAN)
COOLING FANl1o-1
Condenser Jan relay, A'lC compressor clutch relay
Radiator tan relay
&5

Ground-to-Components I ndex
f.,lONOTE: All ground wires are BLK unless otherwise noted.
GroundPageComponents or Circuit Grounded
Battery (BLKYEL)
Steering pump bracket
t+-rg ITransmission housing
l
G101
(-1)
G101
(-2)
14-2
and
14-3
ano
14-1
Powertrain or engine control module (PG1 and pG2 are BLK: LG1 and LG2 are
BRN/BLK), EGR control solenoid valve (CW, EGR valve and lift sensor (Dt6yS enginewith M,/T), Engine coolant temperature switch, pGM-Fl main relay, power steeringpressure switch (USA), Primary HO2S (D16Y5 engine with l\/,/T), Vehicle speed sensor,VTEC pressure switch (D16Y5/D16Y8 engines), CKF sensor (BRN/BLK), Transmission
control module (CYf) (Pc1 is BLK: LG1 is BRN/BLK)
Shielding betvveen the PCM or ECM and these components (all have BRN/BLK wires):
CKF sensor, TDC/CKP/CYP sensor. Primary and secondary heated oxygen sensors.
Knock sensor (CWDl6YB engine), Mainshaft speed sensor (AiT except CVT),
I Countershaft speed sensor (A/T except CVf)
Shielding between the TCM and these components (CVT) (all have BRN/BLK wires):
Drive pulley speed sensor, Driven pulley speed sensor, Secondary gear shaft
speed sensor
Powertrain or engine control module (PG1 and pG2 are BLK; LG1 and LGz are
BRN/BLK), EGR control solenoid valve (D16Y5 engine), EGR valve (Dt685), Engine
coolant temperature switch, Fuel pressure regulator shut-off solenoid valve (D1685),
PGM-FI main relay, Power steering pressure switch (USA), Vehicle speed sensor, VTECpressure switch (All except D16Y7 engine), CKF sensor (A

except 81642) (BRN/BLK)
Shielding between the PCM or ECM and these components (all have BRN/BLK wires):
CKF sensor, TDC/CKP/CYP sensor, Primary and secondary heated oxygen sensors,
Knock sensor (All except D16Y7 engine), i/ainshaft speed sensor (Arf except CW),
Countershaft speed sensor (A,/T except CVf), Drive pulley speed sensor (CW), Drivenpulley speed sensor (CVT), Secondary gear shaft speed sensor (CVf)
I Badiator fan motor, Right front parking/turn signat tight, Right headtight
G20214-4I Cruise control actuator, Left front parking/turn signal lights, Left headlight, Rear window
I washer motor, Windshield washer motor, Washer fluid level switch (,99-'00 Canada)
G401| +-o
and
14-7
Accessory power socket, Brake fluid level switch, Clutch interlock switch (M/T), Clutchswitch (lillT with cruise/D16Y5 engine with MfD, Combination wiper switch (Z wires),
Cruise control main switch, Cruise control unit, Dash lights brightness controller, Data
link connector, Daytime running lights control unit (Canada), Gauge assembly, Horn('96-'97 models), Integrated control unit, Interlock control unit (ArI), Keyless door lock
control unit ('99-'00 models with keyless), Moonroof close and open relays, Moonroof
switch, Park pin switch (A/r), Power window relay, Rear window defogger relay, Rear
window defogger switch ('96-'98 models), Steering lock, Stereo radio tuner (,96-,98
USA: LX, EX, and HX), Turn signal/hazard relay, Windshield wiper motor.....plus
everything grounded through G402
6-6