ac system HONDA CIVIC 1999 6.G Workshop Manual

Supplemental Restraint System (SRS)
(
FUSE 13FUELPUUPFBA UMT)15A
See PowerDistibution,page 10-2.
FUSE 23(sRs)
c801PHOTO 58
SRS MEMORY ERASESTGNAL (MES) CONNECTORPHO|O 111
. To avoid accidental deployment and possible
iniury always disconnect the driver's airbag and
f ront passenger's airbag connectors (automatically
shorted) before working near any SRS wiring.
. CAUTION: Whenever the ignition switch is ON (tt),
or has been turned OFF for less than three minutes,
be caretul not to bump the SRS unit; the airbags
could accidentally deploy and cause damage or
iniuries.
UNDER-DASHFUSE/RELAYBOX
GFY 07)or GFN{18)
GFN
GFYt2l
GFN
GRY0)
GFN
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ALK
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GFY O4)or GRN
SRSUNIT
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iffii'r:fi:*" i tH-
PHOIO 125short contact) | - FCqOtL_________J PHO|A 57
47
GAY (21) or GRN
lgnitionInput(VA)
Driver's
cont.ol
lgnitioninput(VB)MES connector inputSRS indicatorlighl control
Service t------check : Passengefs ;connector ; airbag control , GroundInpu , /+rr I pir-r
Passenger'sai|bag conlrol; prc..t rnpuv, Ourpul
14GRY(5) orGFN
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- How the Circuit Works
'96198 Models
The air delivery system directs the flow of air used
by the heater and air conditioner systems.
Mode Selection
Mode selection is controlled by the mode switches
in the heater control panel and the mode control
motor. When you select a specific mode, voltage is
applied through the dimming circuit to the LED,
which comes on, indicating the mode selected.
Ground is orovided to the mode control motor
though that mode switch. The motor then runs until
the air control door reaches the proper position.
Fresh/Recirculation 56lection
When you press the fresh or recirculation button, a
ground signal is sent from the heater control panel
to the recirculation control motor. The motor then
runs until the recirculation door reaches the proper
position. Battery voltage is also applied through the
dimming circuit to the corresponding LED, and the
LED comes on.
Refer to the Service Manual (Section 21, Heater) for
specitic tests or troubleshooting proc€dures.
'99J00 Models
The heater control panel receives battery voltage at
all times through fuse 47. With the ignition switch in
ON (ll), voltage is supplied to the heater control
panel through fuse 17. The control panel is
grounded at G402.
The heater control panel controls the air delivery
motors, and supplies a 5 VDC reterence voltage to
the air mixture control motor.
The air mixture and mode control motors each
receive inputs trom the heater control panel. The air
mix motor regulates the mixture of cold and hot air
by varying the position of the heater-evaporator doot
The mode control motor controls the direction and
volume of outlet air. The air flow can be directed to
the dashboard vents or the corner vents.
Both the air mixture control molor and mode control
motor are grounded by the h€aler control panel.
The recirculation control motor receives battery
voltage through fuso 17 when the ignition swilch is
in ON (ll). lt regulates the position of the fresh/recirc
door, and is controlled by two position inputs from
the heater control panel ("Recirc" and "Fresh").
Refer to the Service Manual (Section 21, Heater) tor
specific tests or troubleshooting procedures.
61-3

- How the Circuit Works
Battery voltage is supplied through tuse 56 to the
A,/C compressor clutch r€lay contacts at all times.
With the ignition switch in ON (ll), vollage is applied
to the coil of the A,/C compressor clutch relay
through fuse 17. When you push the A,/C switch
ON, and the heater fan switch is in position | , 2, 3,
or 4, a "ground" input is provided to the engine
control module (ECM) or powertrain control module
(PCM) through the l'lC thermostat and the l'lC
pressure switch.
The A,/C compressor clutch relay is grounded by the
engine control module (ECM) or powertrain control
module (PCM). When energized, the A'lC
compressor clutch relay allows battery voltage to
turn on the A,/C comDressor clutch.
The A,/C ON indicator light comes on when the A,/C
system is requested.
A,/C Thermostat
The A'lC thermostat is located on the evaoorator
housing. The A,/C thermostat turns 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. The blower motor will keep running
when the sensor turns off the comDressor.
A,/C Pressure Switch
The fuC oressure switch is located in the condenser
outlet line where refrigerant is in a high
temperature/high pressure liquid state. The switch
will sense abnormally high or low pressure, and
open the circuit. This removes ground, and the
compressor will stop running.
Thermal Protectot
The thermal protector, located on the A,/C
compressor, opens and turns the compressor off if it
senses high temperature. Once the compressor
cools, the switch will close and the compressor will
begin running again.
Refer to the Service Manual (Section 22,
Air Conditioning) for specific tests or
troubleshooting procedures.
62-3

Integrated Control Unit
NOTE: Fuse 31 is hot with lgnition Switch in START (lll) and clutch pedal depressed or A,/T Gear Selector in
PARK (P) or NEUTRAL (N), see Starting System, page 21,21-1, ot 21-2.
See BrakeSystemlndicatorli^hl
FUSE 3IstaaTEaSIGI{AT7AAI
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S€s SiarlingSyslsm, pago 21,21-1. or 21'2.
SEs BrakeSystemlndicetorLight A6
SsaClharSrrESystom
Eog GoundDistlbution,page l,l-7.
L------3c420PHO|O 63vtEw 53
--r-r..r'
FED/BLU
SeeCeilingLightSee Seat Beltand lgnitionKey Remind€rs
t@
i'l-;;,-lH8B'r*| rrmn1gn I FUSEI
i f t*" ig8f"LJr____J PHOTO 7
u'lf tf,%,
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wHr,FED I sYsteh
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Brake System Indicator Light
- '96-'98 Models
NOTE: Fuse 31 is hot with lgnition Switch in START (lll) and clutch pedal depressed or A,/T gear selector in
PARK (P) or NEUTRAL (N), see Starting System, page 21 , 21-1, or 21-2.
a
FUS€ 31atAirEn8Gl{tt7.all
UNDER-DASHFUSE/RELAYBOXS€o Starling Sysl6m,pag6 21, 2l-1, or el-2,
FUSE 25
ffR s." Ponr"tDistribulion,page 10-6.
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Ss€ Pow6rDlstribution,page 1G6.
---.I GAUGE$os IndicatorsI ASSEMBLY
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l8s: GRN/FEDr--- CW ----.
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- '99-'00 Models
NOTE: Fuse 31 isJtot with lgnition Switch in START (lll) and clutch pedal depressed or A,,/T gear selector inPARK (P) or NEUTRAL (N), see Starting System, page 21 ,2i-1, ot 21-2.
UNDER"DASHFUSEiRELAYBOX
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BrakeBulbChsckCheuh
NTEGNATEDcot{TRoLUNITftoa 64vEw a7
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S€6 GroundDistribution,pago 14-7.I
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c551PHOfA 63c419PHO|O 63 |(r;'Used)
1514
r----4(--.1 DAYnMEI q* * |RUNN|NG
Llt:i-ib'f#Iu'"'' i---Y -- """* i
FED/GFN I c419 :
18 Jl iE?'8' :f ?-'! uloen-oasx 'I I I FUSE/RELAY
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I Sss GfoundI Distribution.I pag€ 147.
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L_l.'-4o.'
Fr,lrs 3i
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3m" ) 9ff" s"" po*"r I
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l3.f ftT:4""
Bulbchekoutp$
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GBN/FED II PHOIO 22
5fi ennxe rluroI ' I LEVEL SWITCH
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L__l+: G40lPHOIO 57
l-rlrl PARKTNGI ' I BRAKE SWITCH ,
lIdft"f[]r'"r'" i
c"n"o":- "igt-ol'- - - - - j
71-1

Brake System Indicator Light (cont'd)
- How the Circuit Works
The brake system indicator light comes on to alert
the driver that the parking brake is applied, or that
the brake fluid level is low. lt also comes on as a
bulb test when the engine is cranked.
Parking Brake
With the ignition switch in ON (ll) or START (lll),
voltage is applied through fuse 25 to the brake
system light. When you apply the parking brake, the
switch closes and provides a ground for the light.
The light then comes on to remind you that the
parking brake is applied.
Brake Fluid Level
With the ignition switch in ON (ll) or START (lll),
voltage is applied through fuse 25 to the brake
system light. lf the brake fluid level is low, the brake
fluid level switch closes, providing ground to the
circuit. The brake system light then comes on,
alerting the d verto a low brake fluid level in the
brake master cylinder. (Check brake pad wear
before you add fluid).
Bulb Check
With the ignition switch in START (lll) and clutch
pedal depressed or A'lT gear selector in PARK (P)
or NEUTRAL (N), voltage is applied through fuse 31
to the brake bulb check circuit. The brake bulb
check circuit closes, allowing current to flow through
the brake system light and bulb check circuit to
ground. The brake system light then comes on to
test the bulb.
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
71-2
a
\fa

How the Gircuit Works
All Except GX
Do not smoke while working on the fuel system.
Keep open flame away trom the work area. Drain
fuel only into an approved container.
A thermistor is mounted in the fuel tank unit. When
the thermistor is cool, its resistance is very high.
When the thermistor's temperature increases, its
resistance decreases. Fuel in the fuel tank transters
heat away lrom the thermistor fast enough to keep it
cool so the thermistor's resistance stays high and
lhe low fuel indicator light does not come on. When
the fuel level drops below the thermistor, the
thermistor's temoerature increases. Without the fuel
to cool it, the thermistor's resislance decreases,
allowing current to llow through the low fuel
indicator light and the thermistor to ground, and the
low fuel indicator light comes on.
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
GX
The PCM turns on the low fuel indicator light when
the fuel level is low. The PCM will also blink the
indicator light when a problem is detected by the
fuel tank pressure sensor or the fuel tank
temperature sensor.
Refer to the Service Manual GX Supplement
(Section 11 , Fuel and Emissions) for specific tests
or troubleshooting procedures.
74-1

Indicators (cont'd)
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YEL
YEL
FUSE 2sUETER7.54
.I UNDER-DASH
IFUSE/RELAY
! F,gI".,I
IJ
See PowerDistribution,page 10€.
@f,*+* @sv#ftn* G)ffig^,", t
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?-(: i#i',du), c401 ^t,a PHOfO 1J6I pHOfO 57 v"r vlEW 58
'99- 00 vehicles pre-wired foraccessory security system
I :7 r----r -7 ucHr \
i llEl lH lt*l
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t--J-------Lfe---t---- ---JB8Y BsY B3YB8Y BsY -___B_3_Y_
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+ + l-----il------"rl';r'- ------------i
i "Lu,"r" ! rc;1rg (oPrroN) """"";:"J; !H;fi;"";Jt"'
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i """'^ I ".u"." -4 ELueLx 9 3B"rU"?'JYSJtttt :
See Low See Brake 6 Zl C503Fuel lndicator System ]l Paoro o'Light Inbicator ,____l_'':Y":-, BLU BLK ll _... _.._ q SECURTW SYSTEM, I BLU'BLK .. BLU/8!K : nourpcrrip
Coupe and Sedan
'96197 models
"ar,"a^ fi
'tg::1",,,
BLU/BLK
Jf v/Er,! e'98-'00 models
TRUNK LATCHSWITCHClosed withtrunk open.
"arr"a*l
qF*til'-""
* = Male-Femaleterminals reversedfor'99-'00 models
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80-2

A/T Gear Position Indicator
{\
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@UNDER-DASHFUSE/RELAYBOX
r
See A/TControls
"Ttr
See Dash andConsole Lights
-AYlltFED I FED/BLK I
tl
YEL
A1
SEE A,TTControls,PGM.FI
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A/T GcarPoiltlo{|Indlc{or
GAUGEASSEMBLY
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BLKBLU
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GRNA!/HT
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BLKaLu
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See A,/TControls
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A.t 3
BLKBLU
7
BLK/BLU
eui [SBruI
SeelnterlockSystem
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ar
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-l-rl
c433
A/TGEARPOStTtONswrTcH
Sec GroundDistribution,pag€ 1+7.
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