2000 HONDA CIVIC heater control

Troubleshooting -'99 - 00 Models
Heater Control Panel Input/Output Signals
HEATER CONTROL PANEL CONNECTORS
8P CONNECTOR2OP CONNECTOR12P CONNECTOR
Wire side of female terminals
8P CONNECTOR (O qn Circuit Diagram)
20P CONNECTOR {D on circuit Diagram}
*: with Ay'c
12P CONNECTOR (tr on Circuit Diagraml
CavityWire colorSignalCavilyWhe colorSignal
BLU/8LKBLOWER FEEDBACKINPUT5REDDASH LIGHTS BRIGHTNESSCONTROLLEROUTPUT
2GRN/lVHTFRESHINPUT6BLKGBOU N DOUTPUT
3GRN/REDRECIRCULATEINPUT7BLU/YELREAR WINDOW DEFOGGERRELAYOUTPUT
4RED/BLKCOMBINATION LIGHT SWITCH(Via No. 30 (7.5 A) fuse)INPUT88LfiELlG2 {Power)INPUT
CavityWire colorSignalCavityWire colorSignal
LTGRN/BLKPOWER TRANSISTOR EASEOUTPUT't1BLU/REDAy'C THERMOSTATINPUT
2BRNMHTMODE CONTROL MOTORGROUNDINPUT12BRNAIR MIX CONTROL MOTORGROU NDINPUT
3RE D/YELAIR MIX HOTOUTPUT13ORNAA/HTBLOWER MOTOR HIGHRELAYINPUT
RED,ryvHIAIR MIX COOLOUTPUT14
5YEUBLUMODE DEFINPUTPN K,/BLKAIR MIX POTENTIALOUTPUT
6YEUREDMODE VENTINPUT16
7GRNI/ELMODE HEAT/r'ENTINPUT11
IBLUAVHTMODE HEATINPUT18
9YELMODE HEAT/DEFINPUT19
10WHT/BLU+B (Power)INPUT20GRYAIR MIX POTENTIAL +5 VOUTPUT
CavityWilecolorSignalCavityWi.e cololSignal
lSWITCH LED COMMONOUTPUT1SWITCH LIGHTS +OUTPUT
2ISWITCH LIGHTS -INPUT
39SWITCH COMMONINPUT
4RECIRCULATION CONTROLSWITCH LEDINPUT10A,/C SWITCHOUTPUT
5A./C SWITCH LEDINPUT11RECIRCULATION CONTROLSWITCHOUTPUT
6REAR WINDOW DEFOGGERSWITCH LEDINPUT12REAR WINDOW DEFOGGEBSWITCHOUTPUT
21-36

Blower Unit
Replacement
NOTE: The blower motor, recirculation control motor
and blower resistor can bs replacsd without rsmoving
th€ blower unit (see neld Page).
1. Move the temperature control to "HOT."
'96-98: Slide the temperature control lever.'99-00: Turn the ignition switch ON (ll), then turn
the temperature contol knob. Turn the ignition
switch off,
Remove the glovs box (ses ssction 20),
R€move ths s6lf-tapping screw and ths passsng6r's
dashboard low€r cover. Removo the bolt, the nut
and the kn€e bolst€r, then remove the fiv€ bolts and
the glove box trame,
Without Air Condhioning
4-a. Remove the wiro harness from the h68t€r duct, then
remove the two self-tapping scrsws and the heatsr
duct.
KNEE
GLOVE BOX FRAME
HEATER DUCT
21-37
Wrth Air Conditioning
4-b. Removo th6 ev8porator (sss pago 22-28).
6x1.0m|n9.8 N'm
6x1.0mm9.8 N'm lt'o tgf'm, t.2 lb{'ttl
Disconnoct the connectors trom th€ blower motor,
blowor r6sistor {'96 - 98 models), power transiator
('99 - 0O modsls), blowor motor high telay ('99 - 00
models) and recirculation control motor.
R€mov€ ths wiro harnoss clip from tho recirculation
control motor, and release the wir6 harnsss from ths
clamo on the blowor unit. Remove the two mount-
ing bolts, tho mounting nut and ths blowor unit'
9.8 .m 11.0 tgfm,1.2 tblfrl
lnstall in ths reverso order of removal. Mako surs
that thsre is no air leaka96.
6x1.0mm9,t N'm 11.0lgi.m,7.2 tbf.fil

Heater Unit
Replacement (cont'dl
6.
7.
8.
9.
Remove the dashboard (see section 20).
Remove the heater duct (see page 21-37) or evapo-
rator (see page 22-28).
Disconnect the connectors from the mode control
motor and air mix control motor ('99 - 00 models),
then remove the wire harness clips and wire har-
ness from the heater unit. Remove the clip from the
heater duct, then remove the two mounting nuts
and the heater unit.
6x1.0mm9.8 N.m 11.0 kgl.m,7.2 lbf.ftl
HEATER UNIT
lnstall in the reverse order of removal. Make note of
the following items.
Apply sealant to the grommets.
Do not interchange the inlet and outlet heater
hoses. Make sure that the clamps are secure.
Refill the cooling system with engine coolant
(see section 10).
Connect all cables, and make sure they are prop-
erly adjusted (see page 21-44 (96 - 98 models)
or page 21-45 ('99 - 00 models)).
Make sure that there is no air leakage.
21-40

Heater Control Panel
'95 - 98 modolsi
Remove the driver's dashboard lower cover, the
glove box and the center dashboard lower cover(see section 20).
Disconnect the air mix control cabls from the heater
unit {see page 21-44).
Remove the rear window defogger switch, the hazard
warning switch and the audio unit (see section 23).
Disconnect the connectors from the heater control
panel. Remove the five self-tapping screws and the
center panel together with the heater control panel.
NOTE: The locking tabs are on the bottom of the
connecrors.
Install in the .everse order of removal. Adjust the air
mix control cable and the heater valve cable {seepage 21-44)..
Replacement
1.
Remove the four self-tapping screws and the heater
21-42
1.
'9!, - 00 modols:
Remove the center panel together with the heater
control panel (see section 20).
Remove the self-tapping screws and the heater con-
trol panelfrom the center Danel.
Install in the reverse order of removal. After
tion, operate the heater control panel to see
whether it works properly.
installa-

Overhaul -'96 - 98 Models
HEATER FAN SWITCHTest, page 21-49
Air Mix Control Cable Replacomenl
1. Cut the inner cable on the lever side of the cable holder, then remove both pieces of the inner cable.
2. Using a sharp knife, cut completely through the end of the cable housing at the two locations.
3. Slidethe largesection ofthecable housing outofthe cable holder, being careful not to da mage the cable stops.
4. Carefully remove the cut pieces of the cable housing with a small flat tip screwdriver.
5. Hook the tip of the new air mix control cable to the temperature control lever, then push the cable housing into the
cable holder until it locks into place.
NOTE: After assembly, check that the temperature control lever slides smoothly through the full stroke lrom right to left.
21-43

Temperature Control
Adjustment -'96 - 98 Models
1. From under the hood, disconnect the heater valve
cable from the heater valve.
TERVALVECABLEHEATER VALVE ARM
2.From under the dash, disconnect the air mix control
cable housing from the cable clamp,
AIR MIXCONTROLARM
3.Set the temperature control lever to MAX. COOL.
With the air mix control cable attached to the air
mix control arm, gently pull on the outer cable
housing to fully close the door and to remove any
slack in the cable. Don't pullto hard, or the temper-
ature control lever will move.
Hold the air mix control arm against the stop. then
snap the air mix control cable housing into the
cable clamp.
21-44
6. From under the hood. move the heater valve arm to
the fully closed position. then attach the heater
valve cable to the heater valve arm.
7. Hold the heater valve arm in the closed position,
and gently pull on the heater cable outer housing to
take up any slack. then install the heater valve cable
housing into the cable clamp.
HEATER VALVE ARM

Adjustment -'99 - 00 Models
1. From under the hood, open the cable clamp, then
disconnect the heater valve cable from the heater
valve arm.
From under the dash. disconnect the heater valve
cable housing from the cable clamp, and disconnect
the heater valve cable from the air mix control arm.
HEATER VALVE CABLE
Set the temperature control dial on MAX COOL with
the ignition switch ON {ll).
Attach the heater valve cable to the air mix control
arm as shown above. Hold the end of the heater
valve cable housing against the stop, then snap the
heater valve cable housing into the cable clamp.
HEATER VALVE ARM
5. From under the hood. turn the heater valve arm to
the fullv closed oosition as shown, and hold it,
Attach the heater valve cable to the heater valve
arm, and gently pull on the heater valve cable hous-
ing to take up any slack, then install the heater valve
cable housing into the cable clamp.
HEATER VALVE ARM
21-45

'99 - 00 Models
UNDER DASHFUSE/BELAY BOX
No.l7 (7.54)
BLK
I
G751
$*"
O :8P coNNEcToF
n :20P CONNECToF
E 12P coNNEcroRBLK
d-
G401G402
UNDER HOOD FUSE/RELAY 8OX
N0.41 (P,0A) N0.42 (404)
COMPRESSORCLUTCHFELAY
GNITON SWTCH
HEATER CONTROL PANEL
22-7