1998 HONDA CIVIC Fan switch

- How the Circuit Works
Radiator Fan
Voltage is provided at all times to the radiator fan
relay (contacts) through fuse 57. With the ignition
swilch in ON (ll), voltage is provided to the coil of
the relay through luse 17.
The radiator tan relay can be grounded through
either the engine coolant temperature switch or the
engine control module (ECM) or powertrain control
module (PCM).
The engine coolant temperature switch grounds
the radiator fan relay (coil) when the engine
coolant temperature exceeds 199'F (83'C). The
switch opens when coolanl temperature
decreases 3'- 8'C.
Condenser Fan
Voltage is provided at all times to the condenser fan
relay (contacts) through fuse 56. With the ignition
switch in ON (ll), voltage is provided to the coil of
the relay through fuse 17. When you push the A'lC
switch and put the heater fan switch in 1, 2,3, o( 4
position, the ly'C thermostat comes on, the
condenser fan relay energizes, and the condenser
fan motor runs.
A,/C Thermostat
The A,/C thermostat is located on the evaporator
housing. The A,/C thermostat tums off the A/C
compressor clutch if the temperature at the
evaporator goes below 3'C (37'F). This prevents
condensation from freezing on the evaporator fins
and blocking the air delivery into the passenger
compartment. lf the temperature goes below 3'C
(37"F) tuming off the Ay'C thermostat, ground will be
removed from the condenser fan relay. This will
deenergize the relay and remove voltage from the
condenser fan motor causing the fan to stop running.
Reter to the Service Manual (Section 23, Eleckical)
for specific tests or troubleshooting procedures.
63-3

Gauges (cont'd)
- How the Gircuit Works
When the ignition switch is in ON (ll) or START (lll),
battery voltage is supplied through fuse 25 to the
gauges in the gauge assembly.
Speedometer and Odometer
The odometer and soeedometer drive circuits
receive pulses from the vehicle speed sensor
(VSS). The pulse rate increases as the car
accelerates. The frequency and duration of these
input pulses are measured and displayed by the
speedometer, odometer and tripmeter.
Tachometer
The tachometer drive circuit receives pulses from
the ignition control module (lCM) in the distributor
assembly or the ECM/PCM. The solid-state
lachometer then displays these pulses as engine
speed. For each 200 pulses per minute from the
ignition control modul€ (lCM) or the ECM/PCM, the
tachometer displays 100 RPM.
Engine Coolant Temperature Gauge
The engine coolant temperature gauge has two
intersecting coils wound around a permanent
magnet rotor. Voltage applied to the coils, through
fuse 25, generates a magnetic lield. The magnetic
field, controlled by the coolant temperature sending
unit, causes the rotor to rotate and the gauge
needle to move. As the resistance in the sending
unit varies, current through the gauge coils
changes. The gauge needle moves toward the coil
with the strongest magnetic field.
The 6ngine coolant temperature sending unit's
resistance varies from about 137 ohms at low
engine temperature to between 3H6 ohms at high
temperature (radiator fan running).
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
81-2
(
Fuel Gauge (All except cX)
The fuel gauge has two intersecting coils wound
around a permanent magnet rotor. Voltage applied
to the coils, through tuse 25, generates a magnetic
field. The magnetic field, controlled by the fuel
gauge sending unit, causes the rotor to rotate and
the gauge needle to move. As the resislance in the
sending unit varies, current through the gauge coils
changes. The gauge needle moves toward the coil
with the strongest magnetic field.
The fuel gauge sending unit's resistance varies
from about 2-5 ohms at full, to about 110 ohms at
empty. When you turn the ignition switch off, the
gauge remains at the last reading until you turn the
ignition switch to ON (ll) or START (lll) again,
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
Fuel Gauge (GX)
The fuel gauge has two intersecting coils wound
around a permanent magnet rotor. Voltage applied
to the coils, through fuse 25, generates a magnetic
field. The magnetic field, controlled by the PCM,
causes the rotor to rotate and the gauge needle to
move. The PCM calculates the gas quantity in the
fuel tank by using the fuel pressure value detected
by the tuel tank pressure sensor and the fuel
temperature value detected by the fuel tank
temperalure sensor, and outputs the signal to the
gauge assembly. The gauge needle moves toward
the coil with the strongest magnetic field.
When you turn the ignition switch off , the gauge
remains at the last reading until you turn the ignition
switch to ON (ll) or START (lll) again. When the
PCM detects a malfunction with the fuel pressure or
temperature, or detects a gas leak, the PCM
reduces the fuel meter to 0.
Refer to the Service Manual GX Supplement
(Section 11 , Fuel and Emissions) for specific tests
or troubleshooting procedures.
a
a

-
Component Connector View Index (Views begin on page 202-21
Connector View
ABS Control Unit........ ......63
Audio Unit ('99-'00 models) ......74
Combination Light Switch . . . . . . . . . . . . . . . 64
Combination Wiper Switch . . . . . . . . . . . . . . 65
Cruise Control Unit.... .....43
C\TTTransmission Solenoid ............. 25
Data Link Connector (DLC) ..... 48
Daytime Runnlng Lights Control Unit ..... 66
Engine control Module (ECM) ...........70
Exhaust Gas Recirculation (EGR) Valve
and Lift Sensor (D16Y5 Mfl, D1685) . . . . 10
Gauge Assembly .............71
HazardWarnlngSwitch,,. .,,,...,,,,... 32
Heater Control Panel ('96-'98 models) .....44
Heater Control Panel ('99-'00 models) ...., 76
Heater Fan Switch ('96-'98 models) ,,,.... 11
fniector Control Module (GX) ............77
I/
202-1
Connector View
Integrated Control Unit .......,. 67
f nterfock Control Unit .... ...... 26
Keyfess Door Lock Control Unit . . . . , . . . . . 75
Mode Control Motor ... ........'17
Moonroof Close Relay .. .......13
Moonroof Open Relay ... .......15
PGM-FI Main Relay .. .......... 18
Power Door Lock Conlrol Unil ..... ...... 37
Power Mirror Switch .,... ...... 33
Power Window Master Switch .,.........36
Powertrain Control Module (PCM) .......70
Security Control Unit ..., ..,,... 58
Security Starter Cut Belay ... ...,,,....,, 12
SRS Unit ............. 51
Stereo Radio Tuner ('96-'98 models) ...... 68
Transmission Control Module CICM) .....69

\7. C604 (Hatchback)
GRN/BLK(Back-up lights)
l\4ale GRNIYELFemale - GRN/RED(Turn signaland hazardwarning lights)
BLK (G601)
- Gray- Left rear ol cargo area- Connects rear wire harness to left outer
taillight assembly
4
5
6
1
2
GRNAVHT(Brake lights)
FED/BLK(Headllght switch)
10. Exhaust Gas Recirculation
(EGR) Valve and Lift Sensor
1
2
3
(D16Y5 MfI D1685)
- Gray- Top right side of engine- On engine wire harness
WHT/BLK (EGR input)
GRN/BLK(Sensor ground)
YEUBLU(Reference voltage)
4
5
6
BLK (Ground)
PNK (EGR control)
of cargo area
rear wire harness to right outer
assembly
n- -n
a t | _ a2a
l3I4t5tttl
IJ
I
8. C605 (Hatchback)
- Gray- Right rear- Connects
taillight
GRN/BLK(Back-up lights)
GRNTYEL(Turn signaland hazardwarning lights)
3
4
5
6
1
2
BLK (G601)
GFNAVHT (Brake lights)
RED/BLK(Headlight switch)
11. Heater Fan Switch
('96-'98 Models)
- Brown
Center of dash- On heater-sub B wire harness
BLK (Ground)
BLUAVHT (L4edium
LO speed input)
BLU/BLK(Hl speed input)
4
5
6
1
2
3
BLU (LO speed input)
BLU/YEL (Medium
Hlspeed input)
GFIN (Blowerswitch ON input)
9. C607 (Hatchback)
- Blue- Right side o{ cargo area- On rear wire harness
BLU/BLK (lndicators)
RED/BLK(License lights)
GBN,ryVHT (8rake lights)
LT GBN(Rear wiper/washe0
5
6
1
2
3
4
GRN(Rear wiper/washer)
LT GRN/BLK(Rear \/iper washer)
)/
202-3
12. Security Starter Cut Relay/C416
- Natural* Upper left kick panel- On main wire harness
1
2Allexcept CX and DXI[,4ale: BLK,^r'r'HTFemale: BLKI/ELCX and DXi BLI(WHT(Battery input)
All except CX and DX:BLK^/ELCX and DX: BLK/WHT(Baftery input)
[.4ale - BLK/WHTFemale - BLKAVHTor BLKRED(Starter output)
All excepi CX and DX:RED/YELCX and DX: GRN(Security starter c!1relay control inpul)
5
6
tl3'

-25. CW Transmission Solenoid
- Gray- Lower front of transmission- On engine wire harness
1
2 GRNAVHT (H LC LS +)
3 BLUAVHT (SH LS +)
4 YEL (SC LS +)
5
6
7
8
GRN/BLK (SOL IN H)
PNK/BLK (HLC LS _)
GRN|VEL (SH LS -)
PNK/BLU (SC LS _)
26. Interlock Control Unit
- Gray- Behind left side oJ dash, right of steering column- On main wire harness
1
7
2
3
4
WHT/BLU (Key interlocksolenoid control)
YEL (lgnition input)
YEUBLK (Shift locksolenoid control)
BLK (G401)
WHT (Key
interlock switch input)
BLKBLU (Park lnput)
WHT/RED (Shinlock circuit control)
WHI/BLK(Park pln switch input)
6
7
27. C352
- Gray- On bottom of under-hood {use/relay box- On main wire harness
1
789
I
1
2
3
4
GRN (Fans)
BLUAVHT (fuC
compressor controlS)
WHT/BLK(Hazard warning lights)
WHT/BLK (Fuse 42)
BLKRED (A/Ccompressor clutchrelay control)
BLK,/YEL (Fuse 17)
WHT/GRN (Fuse 52)
WHT (Fuse 48)
6
7
8
I
28. C101
- Gtay- Left rear of engine compartment- Connecls engine wire harness to main wire harness
1 l\,4ale - BLK/YELFemale - BLK,ryVHT(Fuse 15)
2 BLK (G101)
3 YEURED (Oilpressure indicator light)
4 *1/*4: BRN/BLK (G101)
5 YEUBLK (PGI\4,FD
6 WHT/BLU(Charging system)
7 YEL/GRN (Gauges)
I *1: BLU (lgnition
sYstem)
9 Male - BLK VHTFemale - BLKRED(Slarting system)
10 *2: BLKryEL(lgnition system)*3: Male - BLK/YELFemale - RED(lgnition system)
*1= 96-'98 models: All'99: D16Y5 with M,iT*2= '96-'97 models: All'98-'99 modelsr GX*3= '96-'98 models: All except GX*4=: '98''00 Models: GX
202-7

-50. c421
- Green- On rear of under-dash fuse/relay box- On main wire harness
I
l RED/YEL(Headlight switch)
2 BLIVBLU (ABS)
3 RED/GRN(Headlight switch)
4 GFIN/BLK(Front wiper/washer)
5 FED/BLU(Headlight swrtch)
6 WHT/BLU(Charging systern)
7
9 REDAVHT(Headlight switch)
10 GRN/YEL (Turn signaland hazard lights)
11
12 USA: BLKAVHT(Charging system)
13 BLKryVHT (Fuse 15)
14 GRN/RED (Brake
indicator system light)
16 GRN/RED (Turn signaland hazard lights)
17 BED/BLK(Headlight switch)
18 RED/BLK(Headlight switch)
52. C130
- Brown- Below right side ot dash panel- Engine wire harness junction connector
T---------"1
1 8RN/BLK (G101)
2 BRN/BLK (G101)
3 BRN/BLK (G101)
4 BRN/BLK (G101)
5 BRN/BLK (G101)
6 BRN/BLK (G101)
7 BRN/BLK (G101)
I BRN/BLK (G101)
9 BRN/BLK (G101)
10 BBN/BLK (G101)
L---------J
Terminals grouped together areconnected by the sarre bus bar.
*1= 96- 98 models: All except D16Y5'99-'00 models: D1685*2= 96-98 models: D16Y5/D1685'99- 00r All except D1685
11 BLUMHT (VSS)
12 BLU,ryVHT (VSS)
13 BLU,^/VHT (VSS)L_-_____--Jr---------'1
14 YEL/BLK (PGl\4-Fl)
15 YEL/BLK (PGr\4'Fr)
16 YEUBLK (PGI\4,FI)
17 YEUBLK (PGr\4,Fr)L______---JT----------118 *1: GRN (Fans)*2: YEUBLU (PGM-Fl)
19 *1: GRN (Fans).2: YEUBLU (PGM-Fl)
20 *1: GRN (Fans).2: YEUBLU (PGM-Fl)_______--J
51. SRS Unit
- Yellow- Below center oJ dash- On SRS marn wire harness
1 GFY (1) or GRN(Drivefs nflator)
2
3 GRY (17) or GRN(lgn tion input)
6 GRY (21) or GRN(SRS indicalor control)
7 GRY (18) or GRN(lgnition nput)
8 GBY (14) or GRN (MES)
9 GBY (13) of GRN(Service checkconnector input)
10 GRY (4) or GRN(Frt. pass. inflato4
11
13 GBY (2) or GRN(Drivefs nflator)
14 GBY (5) or GRN(Frt. pass. inflator)
15 GRY (3) or GRN(DLC input/output)
16 GRY (19) or GRN(G801)
17 GRY (20) or GRN(G801)
1B GRY (6) or GRN (MES)
13678
10Il12131415't7't8
53. C420
- Green- On rear of under-dash fuse/relay box- On main wire harness
1 Canadar RED/BLU(Headlights)
2
3 8LK (G401)
5 WHT/GRN(Rear window defogger)
6 WHT/BLU(Power windows)
7
8 YEL/GRN (PGM-FD
I BLK//EL (Fuse 17)
1O BLUAVHT (PGM,FI)
1 1 BLUMHT (PGI,4-FI)
14
16 Canada: BLKAVHT(Headlights)
18 A/Tr WHT/GRN(lnterlock system)
19
20 WHT/RED(Ceiling light)
202-15

Connector ldentification and Wire Harness Routing
Connector
or
Terminal
Number of
Cavities/
Color
LocationConnects toNotes
Starter Cables
T1
r2
Right side of engine compartment
Right side of engine
Under-hood luse/relay box
Staner motor
t+lBatteryBattery positive terminal
Battery Ground Cable
Right front shock towerBody ground, via battery ground
cable
oBatteryBattery negative terminal
Engine Ground Cable A
t!tLeft end of enginePower steering pump bracket
Too left side ot bulkheadBody ground, via engine ground
cable A
Engine Ground Cable B
T4Bight side of engine compartmentTransmission
(ritRight side of front frameBody ground, via engine ground
Under-hood ABS Fuse/Relay Box Wire Harness
tcRight side of engine compartmentUnder-hood ABS fuse/relay box
oBatteryBattery positive terminal
A,/C Wire Harness
c209
wtJl/,\-7Ee
c754
4-GRY
1.GRY
2-GRY
2-GRY
Lefl front of engine compartment
Left front of engine compartment
Lefl front of engine compartment
Left tront of engine compartment
Engine compartment wire harness
A,/C compressor clutch
Condenser fan motor
A,/C pressure switch
G751Left front of engine compartmentBody ground, via A,/C wireharness

Connector ldentification and Wire Harness Routino
Connector
or
Terminal
Number of
Cavities/
Color
LocatlonConnects toNotes
Engine Compartment Wire Harness
c201
c202
c202
UZUJ
c204
c205
c206
c207
c208
c209
c210
c210
c212
c213
c214
c215
1O-BLU
6.GRY
2.GRY
4-GRY
2-GRN
2-BRN/VVHT
3-GRY
1.BRN
q-u11 r
2.GRY
1-BLU
or BLK
2-GRY
3-BLK
3-GRY
8.GRY
2-GRY
Lefl side of engine compartment
Left side of engine compartment
Left side ol engine compartment
Left side of engine compartment
Behrnd front bumper
Behind front bumper
Left side of engine compartment
Behind front bumper
Left side of engine compartment
Left front of engine compartment
Behind front bumoer
Behind front bumoer
Right front of engine compartment
Right side ot engine compartment
Right side of engine compartmont
Right side of engine compartment
Behind front bumoer
Main wire harness
Main wire harness
Main wire harness
Cruise control actuator
Windshield washer motor
Rear window washer motor
Left front turn signal/parking light
Front tog light
Left headlight
A,/C wire harness
Horn
Horn
Radiator fan motor
Right headlight
Right tront turn signal/parking light
Main wire harness
Washer level switch
'1
"1
Optional
'96-'97
models'98-'00
models
Canada'99r00
models
G201
G202
Right side of engine compartment
Left side ot engine compartment
Body ground, via enginecompartment wire harness
Body ground, via engine
comDartment wire harness
'1 : With cruise control'2: Without cruise control
203-16