1998 HONDA CIVIC Model

Troubleshooting -'99 - 00 Models
Symptom
Mode control motor does not run, or one or more modes are inoperat've'
Recirculation control door does not change between Fresh and Recirculate'
Blower motor only runs on high speed position; it does not run in any other speed positions
Blower motor does not run at all.
Both heater and Ay'C do not work
See pags
a1_tq
21-21
21-29
21-31
21 35
Symptom Chart
For electrical malfunctions which are indicated by the self-diagnostic system, refer to self-diagnosis function (see next
page).
Note these items before troubleshooting a symptom'
. Check the engine coolant level, and allow the engine to warm up before troubleshooting'
. Any abnormality must be corrected before continuing the test
.Becauseoftheprec|semeasurementsneeded,UseadigitaImu|timeterwithanoutputoflmAor|essatthe20ko
range when testing
. Before performing any troubleshooting procedures check:
- Fuses No. 41 115 Al, No 55 (40 A)]n the under-hood fuse/relay box' and No 17 (7 5 A) in the under-dash fuse/relav
box- Grounds No. G401, G402
- Cleanliness and tightness of all connectors
21-19

Troubleshooting -'99 - 00 Models
Self-diagnosis Function
The heater control panel has a self-diagnosis function.
Running the Self-diagnosis Funqtion
Set the mode control dial to the Vent position, and turn the ignition switch ON fll). Within six seconds after turnang the igni_tion switch on. press the recirculation control switch the required number of times depending on the recirculation indicatorlight status:
.lftheindicatorlightisON,presstherecirculationcontrolswitchfivetrmes.
.lftheindicatorlightisOFF,presstherecirculationcontrol switch six rrmes.The recirculation indicator light will come on for two seconds. then blink the Diagnostic Trouble code {DTc} to indicate afaulty component. lf no DTc's are found, the indicator light will not blink after the initial two second liqht.
DTC Indication Pattern (S6e DTC 2l:
Recirculationindicato.light on
Recirculationindicatorlight off2 sec
,/1.5 soct
' 0,3 secWithin six seconds atter theignition switch is turned ON (lll,pross the recirculation controlswitch the required number ottimes depending on the rocircu-lation indicetor light status
0.3 sec
VENT POSITIONMODE CONTROL DIAL
RECIRCULATIONCONTROL SWTCH
DTC Troubleshooting Index
Diagnostic
trouble
code (DTCI
Rgcirculation
indicator lightComponent with problemPossible causeSee page
One blinkAir mix control motorObstructed door, laulty motor21-21
2Two blinksAir mix control motorOpen or short circuit21-23
ln case of multiple problems, the recirculation indicator light will indicate only one DTc with the least number of blinks.
Resetting the Self-diagnosis FunctionTurning the ignition switch OFF will cancel the self-diagnosis function, After completing repair work, run the setf diagnosisfunction again to make sure that there are no other malfunctions.
21-20
@
At
V'

Troubleshooting -'gg - 00 Models
Air Mix Control Motor (cont'dl
Frcm page21-21
AIR MIX CONTROL MOTOR5P CONNECTORWire side ot female terminals
Check fo..n open in the wires:Check for continuity between lol-lowing terminals of the heatercontrol panel 20P connector andthe air mix control motor 5P con-
20P: 5P:No3 _ No. 1No.4 - No.5
Repair any open in the wiro(s)bdtwoon tha hoator control panaland air mix control motor.
Check for loo3e wires or poorconneclions at the heater controlpanol 20P connoctor and at theair mix control motor 5P connoc-to.. It the connections .rc good,substitute a known-good hoaiercontrol panel, and rech6ck. lf thesymptom/indicrtion goes away,replac6 the original heater con-trol panel.
21-22

Troubleshooting -'99 - 00 Models
Check tor a short to power:
Check the same terminals forvoltage.
Rapair short to pow6r in thewirelsl botween the heater con-trol panel and the ai. mix controlmolor. This short also damag.sthe heater control panel. Ropairthe short to power betoro replac-ing the heater control panel.
ls there any voltage?
Check for an open in the wire3:Check for continuity between following terminals of the heatercontrol panel 20P connector andthe air max control motor 5P connector.20Pt 5P:No3 _ No. 1No 4 _ No. 5No_ 12 - No. 2No. 15 - No.4No 20 - No.3
Bepair any open in the wire(s)between the heator control paneland air mix control motor,
Check tor loose wires or poorconnections at the heator controloanel 20P connector and at th.air mix control motor 5P connec-tor, ll the connections rre good,substitute a known-good heatercontrol oanel. and recheck. lf thesymptom/indication goes awry,replace the original heater con-trol oanel,
Air Mix Control Motor (cont'dl
From page 21-23HEATER CONTROL PANEL 2OP CONNECTOR
AIR MIX CONTROL MOTOR5P CONNECTORWire side of lemale terminals
Wire side of female terminals
21-24

Troubleshooting -'gg - 00 Models
Mode Gontrol Motor (cont'dl
From page 21-25
MODE CONTROL MOTOR ?P CONNECTORWire sade of lemale terminals
Chock tor a short to ground:1. Turn the ignition switch OFF.2. Check the same terminals forcontinuity to body ground.
Repair any 3hort in the wirelslbetween the heater control paneland ihe mode control motor.
ls there continuity?
Check lor.n open in tho wires:1, Disconnect the mode controlmotor 7P connector.2. Check for continuity betweenthe following terminals of theheater control panel 20P connector and the mode controlmotor 7P connector.2OP: lPiNo.2 - No.7No.5- No.2No.6- No.6No.7 - No.5No.8- No.4No.I - No.3
Repair any opon in the wire(s)t€tween the h€ater control paneland tha modc contol motor.
ls there continuity?
Check for loose wiaes or ooorconnections at the heater controlpanel 20P connector rnd at themode control motor 7P connec-toa, lf the connoctions ere good,substitute a known-good heatercontrol panol, and recheck. lf thesyfiptom/indication goes away,replac€ the original hoater controlpanel.
HEATER CONTROL PANEL 2OP CONNECTOR
Wire side of female terminals
21-26

Troubleshooting -'99 - 00 Models
Recirculation Control Motor (cont'd)
Frcm page 21-27
HEATER CONTROL PANEL 8P CONNECTOR
Check for a short to power in the
1. Turn the ignition switch ON {ll).2. Disconnect the heater controlpanel 8P connector.3. Check for voltage between theNo.2 and No. 3 terminals oftheheater control panel 8P con,nector and body ground individually.
Repair 3hort to powe. in thewire{a) b.tween tho haetor con-trol panel and the recirculationGontrol moto.. This short alsodamagos the heate. controlpanel. Repair the short to powerb€tore .eplecing the h€ater con-trol panel.
ls there any voltage?
Check to. a short to ground:1. Turn the ignition switch OFF.2- Check the same terminals forcontinuity to ground.
Roprir lhon in tho wir.{s) b€tweothe horter control panel and theracircr alion conhol motoa.
Check for an open in the wires:1. Disconnect the recirculationcontrol motor 4P connector.2. Check for continuity betweenthe following terminals of therecirculation control motor 4Pconnector and the heater con,trol panel 8P connector.8P: 4PiNo.2 - No.2No.3 - No.4
Repair open in ths wirolsl betw€€nthe heate. co.rkol panol and therecirculation control motor .
Check lor loo3a wires or pootconn€ctions at the hoater controlpanel 8P connector and at theaecirculation control motor ilPconnector, It tho connections aregood. substitut€ e known-goodheatei control panel, and aecheck.lf th€ symptom/indication goesaway, replace the original hedtercontrcl Danel.
GRN/WHT
I1
GRN/RED
RECIRCULATION CONTROL MOTOR4P CONNECTORWire side of female terminals
21-28

Troubleshooting -'99 - 00 Models
Blower Motor Speed (cont'dl
HEATER CONTROL PANEL 2OP CONNECTOR
Wire side oJ female terminals
Wire side ot female terminals
Frcm page 21.29
LT GRN/BLK
Check tor a short in the wi.a:Check for continuity between theNo. 1 terminal of the heater control panel 20P connector and bodyground.
Repair short in ths wire betwsenthe hoater control panel and theoower transastoa.
Check for an open in the wire:1. Disconnect the heater controlpanel 8P connector,2. Turn the ignjtion switch ON 1ll).3. Measure the voltage betweenthe No. 'l terminal of theheater control panel 8P connector and body ground.
Repeir open in the wiio betweenthe heater control panel and theblower motoa.
Check the power transistor:1. Turn the ignition switch OFF.2. Reconnect the heater controlpanel 8P and 20P connectors.3. Test the power transistor {seepage 21 50).
ls the power transistor OK?
Check for loos€ wiras or poor con-nections at the h€at€r controlpanel 8P and 20P connectols andat th6 power transistor 3P conn€c-tor. lf the connections are good,substituto a known-good hoatercontrol panel, and recheck. It thesymptom/indication goes away,replace the original heater controloanel,
HEATER CONTNOL PANEL 8P CONNECTOR
21-30

Troubleshooting -'99 - 00 Models
From page 21-31
Check the blower motor relay:1. Turn the ignition switch OFF.2. Remove the blower motorrelay from the under hoodfuse/relay box, and test it- (seepage 21'49).
Replace the blower motor relay.
Check the under-hood tuse/relaybox:Measure the voltage between theNo. 3 terminal of the blowermotor relay 4P socket and bodyground.
Check tor an open in the wire:1. Turn the ignition switch ON (ll).
2. Measure the voltage betweenthe No. 4 terminal of theblower motor relay 4P socketand body ground.
Repair opon in lhe wire betweenthe No. 17 fuse and the blowetls there battery voltage?
Check for an open in the wire:1. Turn the ignition switch OFF.2. Check for continuity betweenthe No. 2 terminal of theblower motor relay 4P socketand body ground.
Check lor an ooen in the wirebetween the blowor motor relayand body ground. It the wiie isOK, check for poor ground atG401 and G402.
ls there continuityl
Repair open in the BLU/WHTwiae between the blower motorrelay and the blower motor,
BLOWER MOTOR RELAY 4P SOCKET
21-32