Heater motor HONDA CIVIC 1998 6.G Workshop Manual

lllustrated Index
@@ system is under high pressure when theengine is hot. To avoid dangsr of rsleasing scaldingengine coolant, removo the cap only when the engine iscoot.
Total Cooling System Capacity flncluding heater andfoservoir (0.4 f (0.42 US qt, 0.35 tmp qt)ll:
*2: 81642 engine*3: D16Y7 engine*4: D16Y8 engine
CAUTION: lf any engine coolant spills on painted por-tions of the body, rinse it off immediately.
NOTE:
. Check all cooling system hoses for damage, leaks ordeterioration and replace if necessary.. Check all hose clamps and retighten if necessary.. Use new O-rings when reassembling.
RADIATOR CAPPressure test, page '10 86x1.0mm9.8 N.m {1.0 kgtm,7.2 tbt.ltl
UPPERRADIATORHOSE
UPPER BRACKETAND CUSHION
COOLANT
RAOIATOREngine coolant refilling and bleeding,page 10 7Leak test, page 10-9Inspect soldered joints andseams for leaks,Blow out dirt Irom betweencore fins with compressed air.lf insects, etc,, are cloggingradiator, wash them off withrow pressure water.
RESERVOIR
5x0.8mmA: ,1.4 N.m {0.45 kgf.m, 3.3 tbtftlg: 5.4 N.m (0.55 kgtm.4.0 tbf.ft)
6x1.0mm7.2 N.m (0.73 kgt.m,5.3 tbtftl
LOWERCUSHION
RADIATOR FANBADIATORFAN
DRAINPLUG
O-RINGReplace.
LOWEBRADIATORHOSE
FAN MOTOR SHROUD
Ar TOYO RADIATOR manufactured radiatorB: NIPPONDENSO manufacfared raoraror
10-2
Refer to section 14when installing.
Mt-|-4.2 f (4.4 US qt,3.7 tmp qt)*j
5.0 / (5.3 U$ q1, 4.4 16p q11*z
4.1 f (4.3 US qt, 3.6 lmp q0*3
4.31 (4.5 US qt, 3.8 tmp qt)*a
CVT4.3 f (4.5 US qt,3.8 Imp qt)
*1i D16Y5, D16Y7, D16Y8 engines
iil

Heater
lllustrated Index
'96 - 98 Models ................................ 21'2
'99 - 00 Models ................................ 21'3
Circuit Diagram
'96 - 98 Models .....21-4
'99 - 00 Models ................................ 21-5
Troubleshooting - '96 - 98 Models
Symptom Chart ............................... 21-6
Heater Control Panel Input/
Output Signals ..............,.............. 21-7
Flowcharts
Blower Motor Speed ................... 21-8
Bf ower Motor ,...21'10
Mode Control Motor ............... ,.'.' 21-13
Recirculation control Motor ....... 21-16
Heater Control Panel ................ ... 21 -14
Troubleshooting - '99 - 00 Models
Symptom Chart ............................... 21-19
Seff-diagnosis Function ............,,,.... 21-20
Flowcharts
Air Mix Control Motor ......,.......... 21-21
Mode Control Motor ............... ..... 21 -25
Recirculation Control Motor ....... 21-27
Bf ower Motor Speed .............. .....21'29
Bf ower Motor ....21-31
Heater Control Panel ................,.. 21-35
Heater Control Panel Input/
Output Signals ............................. 21-36
Blower Unit
Repf acement .........21-37
Overhaul ................ 21-38
* Heater Unit
Replacement ....'....21-39
overhaul """" """' 21-4'l
Heater Control Panel
Repfacement .........21'42
Overhaul -'96 - 98 Models ........... 21-43
Temperature Control
Adjustment - '96 - 98 Models """" 21-44
Adiustment - '99 - 00 Models .......21-45
Air Mix Control Motor
Test - '99 - 00 Models ...........' .......21'46
Replacement - '99 - 00 Models ....21'46
Mode Control Motol
Test ................, .,...'.21'47
Replacement '.'."...21-47
Recirculation Control Motor
Test ................. .......21-48
Repf acement ......." 21-48
Relays
Test ................. .......2'l-49
Heater Fan Switch
Test - '96 - 98 Models ............. .......21-49
Mode Control Switch
Test -'96 - 98 Models ..........."....... 21-50
Power Transistor
Test - '99 - 00 Models ....'........ ....".21-50
*: Read SRS Drecautions before working in this area.

lllustrated Index
'96 - 98 Models
SRS components are located in this area. Review the SRS component locations, precautions, and procedures in the SRS
section {24) before performing repairs or service.
BLOWER UNITReplacement, page 21-37Overhaul, page 21-38
HEATER UNITBeplacement, page 21-39Overhaul, page 21-41BLOWERRESISTOBTest,
CONTROL MOTORTest, page 21-48Replacement, page 21'48
a/c swtTcH{wirh A/c)
MOO€MOTORTest, page 21 47Replacement, page 21'47
AIR MIX CONTROL CABLEAdjustment, page 2'1-44Replacement, page 21'43
HEATER FANswtTcHTest, page 2l'49
MODEHEATER CONTBOLPANELswrTcHEsTest, page 21 50Rgplacement, page 2'l-42Overhaul, page 21-43
TEMPERATURE CONTROLLEVERAdiustment, page 21 44
Detroster-aqtivated A/C System
Turning the defroster on activates the A,/C and sets the air flow mode to FRESH. lt is possible to turn the A,/C off or to
change the air flow to RECIRCULATE by pressing the A/C bunon or the FRESH/RECIRCULATE button.
21-2

'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

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