heater HONDA CIVIC 2000 6.G Service Manual

'99 - 00 Models
SRS components are located in this area, Review the SRS component locations, precautions, and procedures in the SRS
section (24) betore perfoming repairs or service.
HEATER UNITReplacement, page 21'39
Overhaul, page 21-41
BLOWEB UNITReplacement, page 21-37Overhaul, page 21 38
HEATER FANswtTcH
RECIRCULATIONCONTROL MOTORTest, page 21-48Beplacement, page 21-48
AIR MIX CONTROL MOTOBTest, page 21-46Replacement, page 21 46
BLOWERTest, page 21-49
POWER TRANSISTORTest, page 21 50
HIGH RELAY
MODE CONTROLDIALHEATER VALVE CABLEAdjustment, page 21 45TEMPERATURE CONTROLDIALAdjustment, page 21-45
REAR WINDOWDEFOGGERswtrcHSee section 23MODEMOTORTest, page 21 47Replacement, page 2 l-47A/C SWTTCH
lwith A/cl
CONTROL SWITCH
21-3

'99 - 00 Models
UNDER,HOOO FUSE/RELAY 8OX
PUSN SWITCH
lHce nvosrar F)- aLu neo(Wirh IVC)
DASH LIGHTS -/1BBTGNTNESS < l- FEoCONTROLLER -!
IGN TION SW TCHUNDEF DASHFUSElRELAY BOX
**,',,* **",@ ",.
@f
u,n,",,
ELUAVHT
I
YBLUi BtK
BLOWERMOTOR
ELOWERMOTORHIGHRELAY
PNK/BLK
FED''WHT
RED,YEL
GRY
BRN
YEL
YEL/FEO
6RNiYEL
8LU/!VHT
YEL/BLU
BRNfiHT
GFNM/HT
GRNi FED
O :8P CONNECTOR
! :20P CONNECTOF
E : 12P CONNECToR
BLUi BLK
1
tic
HEATER CONTROL PANEL
VENT
MOOEHEAT CONTFOLMOTOF- M.COMDEF
[[f&H,,4*,",,
BLK

Troubleshooting -'96 - 98 Models
Symptom Chart
NOTE;
. Check the engine coolant level. and allow the engine to warm up before troubleshooting.
. Any abnormality must be corrected before continuing the test.
. Because of the precise measurements needed. use a multimeter when testing.
o Before performing any troubleshooting procedures check:- Fuses No. 41 11.5 Al, No. 55 (40 A) in the under-hood fuse/relay box. and No. 17 (7.5 A) in the under-dash fuse/relay
box- Grounds No. G401, G402- Cleanliness and tightness of all connectors
SymptomRomedy
Hot air flow is low.Blower motor runs. but one or more
speeds are inoperative.
Perform the procedures in the flowchart (see page 21-8).
Blower runs properly.Check for the following:. Clogged heater duct. Clogged heater outlet. Incorrect door position
No hot air flow.Blower motor does not run at all,Perform the procedures in the flowchart (see page 21-10).
Blower motor runs.Check for the following:. Clogged heater duct. Clogged blower outlet. Clogged heater valve. Faultv air mix door. Heater valve cable adjustment (see page 21-44). Air mix control cable adiustment (see page 2'l-441. Faulty cooling system thermostat (see section 10). Clogged evaporator (with air conditioning). Frozen evaporator {with air conditioning)
Mode control motor does not run, or one or more modes
are inooerative.
Perform the procedures in the flowchart (see page 21-13).
Recirculation control door does not chanqe between
FRESH and RECIRCULATE.
Perform the procedu.es in the flowchan (see page 21-16).
Both heater and A,/C do not work.Perform the procedures in the flowchart (see page 21-18),
21-6

Heater Control Panel Input/Output Signals
HEATER CONTROL PANEL lilP CONNECToR
Wire side of lemale terminals
21-7
Terminal
No.
Wire
colorSignalTerminal
No.
Wire
colorSignal
1YELHEAT/DEFINPUT8YEVREDVENTINPUT
BLfiELINPUT9G RNI/ELHEATIr'ENTINPUT
WHT/BLU+BINPUT'10BLKGROUNDOUTPUT
4YEUBLUDEFINPUT11*BLU/REDA./C THERMOSTATINPUT
5REDDASH LIGHTS
BRIGHTNESS CONTROLLEROUTPUT12GRN/WHTFRESHINPUT
6RE D/8LKCOMBINATION LIGHT
SWITCHINPUT13GRN/REDRECIRCULATEINPUT
1BLUMHTHEATINPUT14GRNHEATER FAN SWITCHOUTPUT

Troubleshooting -'96 - 98 Models
Blower Motor Speed
HEATER FAN SWITCH 6P CONNECTOR
Wire side of female terminals
21-a
Blower motor runs. but one orrnore speeds are inoperative,
Chsck for a short or an open inthe wire{s}:Turn the ignition switch ON {ll),and the heater fan switch OFF.
Does the blower motor run?
Check for a shon in th6 wirels):1. Turn the ignition switch OFF.2. Disconnect the blower motor2P connector,3. Remove the center dashboardlower cover (see section 20),and disconnect the heater lanswitch 6P connector,4. Disconnect the blower resistor 4P connector,5. Check for continuity betweenthe No. 2,3, 4 and 5lerminalsof the heater fan switch 6Pconnector and body ground
individually.
ls there continuity?Reolace the heater fan switch,
Repair short in the wire(s)beiween the blower resistor, theheater tan switch and the blowermotor,
To page 21 9

ls there approx. 2 - 3 ohms?
Check for an open in the wire(s):1. Reconnect the blower resistor
4P connector,2. Remove the center dashboardlower cover (see section 20),and disconnect the heater fanswitch 6P connector.3. Turn the ignition switch ON (ll).
4. Ground each of these termi-nals individually in the tollow_ing order: No. 4, 2, 5 and 3.
Does the blower motor run atprogressively higher speeds?Reolace the hoater fan switch.
Repair open or cause ol excessiveresistance in the appropriatewire{sl between the blower resis-tor and the heater {an switch.
Check the blower resislor:1. Turn the ignitjon switch OFF.2. Disconnect the blower resistor 4P connector.3, N4easure the resistancebetween the No. 2 and No. 4
terminals of the blower resis-tor,
BLOWER RESISTOR
HEATER FAN SWITCH 6P CONNECTOR
BLU/WHT
2
16
BLUBLU/YEL
BLU/BLK
JUMPERWIRE
Wire side of female terminals
21-9

From page 2l 10
Check for an open in the wire:
1. Turn the ignition switch OFF,and disconnect the iLrmPer
2. Remove the center dashboardlower cover (see section 20),
and disconnect the heater fanswitch 6P connector.3. Turn the ignition switch ON (ll).
4. Measure the voltage between
the No. 3 terminal and bodygrou nd.
Repair op.n in th6 wiro betw€enthe blower motor and tho heaterfan switch.
Check for an open in the wire:
1. Turn the ignition switch OFF.2. Check for continuity between
the No. 1 terminal of the heatertan switch 6P connector and
body ground.
Reolaco tho heater fan iwitch
Check tor an op€n in the wire
betw.en the heater tan switchand body ground. ll th€ wilo b OK,
check tor poor ground at G401 and
G102.
HEATER FAN SWITCH 5P CONNECTOR
Wire side oI female terminals
(cont'd)
21-11

Troubleshooting -'96 - 98 Models
Mode Control Motor lcont'dl
From page 2l-13HEATER CONTROL PANEL lilP CONNECTOR
Wire side of lemaie terminals
Check tor a short in the wi.e(s):1. Remove the center dashboardlower cover (see section 20),and disconnect the heater con-trol panel 14P connector.2. Check for continuity betweenthe No. 1, 4, 7, 8 and 9 termi-nals and body ground individ-
Raprir.ny short in the wire(s)betw€en the mode control motorand the heater control panel.
Check for a shon to power:
Check the same wires {or voltage.
Repair short to pow6r in thewiro(3) betwoen the mode con-lrol motor .nd tha heate. controlprnel, This short also damag.stho heater cont.ol prnel. Repailthe short to power b€{ore replac-ing the heeter conlrol pan6l.
ls there any voltage?
To page 21 15
21-14

From page 21-14
Check tor an open in the wire{s}:
Check for continuity between the
following terminals of the mode
control motor 7P connector and
the heater control Panel 14P con-
nector-7P: 14P:No.2 - No.4No.3 - No. 1No.4 - No.7No.5 - No.9No.6- No.8
Repair any opsn in the wirels)
bctwoan the mode control motor
and the hoator conlrol Panolls there continuitY?
Check Io. loo3. wires or Poorconnoctions at lhe hoat€r control
Danel 14P connactor, and 3t the
mod6 conilol motot 7P connec-
tor. It tho connoctions ara good.
rsDlaco the heat€r coilttol panel.
HEATER CONTROL PANEL 14P CONNECTOR
Wire side of {emale terminals
MODE CONTROL MOTOR 7P CONNECTOR
Wire side of female terminals
21-15

From page 21-16
ls there any voltage?
Check {or a short in the wire(s):1. Remove the center dashboardlower cover (see section 20),
and disconnect the heater con_
trol panel 14P connector'
2. Check for continuity between
the No. 12 and No. 13 termi-
nals and body ground individ-
Repair 5hort in the wire{sl between
the recirculation control motor and
the heater control Panel
Check Ior a short to Power:Check the same wires for voltage
Repair short to Power in the
wire {s) between the recirculationcontrol motor and the heater
control panel. This short also
damages the heater controlpanel. Repair the short to Powerbetore replacing the heater con-
trol panel.
Check lor an open in the wire(s):
Check for continuity between the
following terminals of the recircu
lation control motor 4P connector
and the heater control Panel 14P
4P. 14P:No.2 - No. 12No.4 No. 13
Repair open in the wirelsl
between the recirculation control
motor and the heater controlpanel.
ls there continuitY?
Check for loose wires or Poorconnections at the heater control
Danel 14P connector, and at the
recirculation control motor 4P
connector. lf the connections aregood, replace the heater control
Danel,
HEATER CONTROL PANEL 14P CONNECTOR
I;-?45
789'o lx11121314
GRN/WHT
0) (0
GRN/BED
Wire side of female terminals
GRN/RED
GRN/RED
RECIRCULATION CONTROL MOTOR
4P CONNECTOR
Wire side of female tetminals
I23i--?156
78I'olx11121314
GRN/WHT
V)(v
145
7IIrol\l rr1213
GRN/WHT
r zl/lt
21-17