1999 HONDA CIVIC no. 25

Troubleshooting -'99 - 00 Models
Blower Motor {cont'dl
BLOWER MOTOR HIGH RELAY 4P CONNECTORWire side of female terminals
BLU/BLK
BLU/ALK
HEATER OONTROL PANEL 8P CONNECTORwir€ sido ot f€male torminals
HEATER CONTROL PANCL 2OP CONNECTORWire side of female terminals
From page 21-33
Check tor an opgn in the wiro:1. Disconnect the heater controlpanel 8P connector.2. Check lor continuity betweenthe No. 1 terminal of theheater control panel 8P con-nector and the No. 1 terminalot the blower motor highrelay 4P connector.
Repsi. op€n in the wir. betw.enthe h..t.r contrcl p.ncl .nd thoblowar motor high rahy.
Ch€ck for an opon in the wir6:1. Disconnect the heater controlpanel 20P connector.2. Check for continuity betweenthe No. 13 terminal of theheater control panel 20P con-nector and the No. 4 terminalof the blower motor highrelay 4P connector.
Ropair opon in tho wiro botwoontha hartor cor rol pangl rnd thablower motor high .elay.
Ch.ck for looso wiros or poor
conn€dions at th6 heato. controlpanel 8P and 20P connectoB andat the blowol motor high relty4P connoctor. It tho connoctionsare good, substitute a known-good heatcr control panel, andrecheck. It the symptom/indica-tion goos away, rgplaco the oiigi-nal heater control oanol.
2
34
o
t2
a568
I23a5078I10
11121315,/1,/1,/m
ORN/WHT
o
12
34
OBN/WHT
21-34

Both heater and A/C do nol work.
checkthe No.47 (7.5 A)fuse in the
under-hood fuse/relay box, and theNo. 17 {7.5 A) fuse in the under-
dash fuse/relay box.
ReDlace the tuse{s), and recheck.
Check lor an open in the wire:
1. Disconnect the heater controlpanel 8P connector,2. Turn the ignition switch ON (ll).
3. Measure the voltage between
the No. I terminal of the
heater control panel 8P con-
nector and body ground.
Repair open in the wire betweenthe No. '17 luse and th6 heatercontrol oanel,ls there battery voltage?
Check for an open in the wire:
1. Turn the ignition switch OFF.
2. Disconnect the heater controlpanel20P connector.3. Measure the voltage lletweenthe No. 10 terminal of theheater control Panel 20P con-nector and body ground.
Repair op6n in the wir€ between
the No. il7 tuse and the heater
controloanel,ls there battery voltage?
Check for an open in the wite:Check for continuity between theNo. 6 terminal of the heater con
trol panel 8P connector and bodyground.
Ch6ck tor an open in lhe wire
betwoen the heator control Paneland bodv ground. lf the wire isOK, check for poor ground atG401 and G402.
ls there continuity?
Check for looso wires or Poolconneciions at the heater controloanel 8P and 20P connectors. lf
the connections are good, substi'
tute a known-good heat€r con-trol Danel, and recheck. lI thesymptom/indication goes awaY,r6place the original h€ater con-troloanel.
HEATER CONTROL PANEL 8P CONNECTOR
BLK/YEL
Wire side of female terminals
HEATER CONTROL PANEL 2OP CONNECTOR
Wire side of temale terminals
I2
1578
BLK
o
1
4I
v

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

Air Mix Gontrol Motor
't.
Test -'99 - 00 Models
Disconnect the 5P connector from the air mix con-
trol motor.
Connect battery power to the No. 1 terminal of the
air mix control motor, and ground the No. 5 termi,
nal; the air mix control motor should run, and stop
at MAX HOT. lf it doesn't, reverse the connections;
the air mix control motor should run, and stop at
MAX COOL.
lf the air mix control motor does not run, remove
it, then check the air mix control linkage and
doors for smooth movement.
lf they move smoothly, replace the air mix con-
trol motor.
AIR MIX CONTROL MOTOR
Measure the resistance between the No.2 and No.3
terminals. lt should be approximately 4.8 to 7.2 kO.
Measure the resistance between the No. 2 and No. 4
terminals. lt should be approximately 3.84 to 5.76 kO
at MAX HOT and approximately 0.96 to 1.44 kO at
MAX COOL.
21-46
5P OONNECYOB
Replacement -'99 - 00 Models
1, Disconnect the 5P connector from the air mix con-
trol motor. Remove the self-tapping screws, the airmix control motor and the flange collar.
CONTROLMOTOR
Install in the reverse order of removal. After installa-
tion, make sure the air mix control motor runs
smoothly.

Mode Control Motor
2.
Test
1.
4.
Disconnect the 7P connector from the mode control
motor.
Connect battery power to the No, 1 terminal, and
ground the No.7 terminal,
CAUTION: Never connecl the battery in iho oppo-
site direction.
Using a jumper wire, connect the No. 7 terminal
individually to the No. 2,3, 4,5 and 6 terminals in
that order. Each time the connection is made, the
mode control motor should run smoothly and stop.
NOTE: lf the mode control motor does not run when
jumping the first terminal, jump that terminal again
after jumping the other terminals. The mode control
motor is OK if it runs when jumping the first termi-
nal again.
MODE CONTROL MOTOR
lf the mode control motor does not run in step 3,
remove it. then check the mode control linkage and
doors for smooth movement. lf they move smoothly,
reolace the mode control motor,
Replacement
1. Disconnect the 7P connector from the mode control
motor,
Remove the rod from the arm of the mode control
motor.
Remove the tyvo self-tapping screws and the mode
control motor.
lnstall in the reverse order of removal. After installa'
tion, make sure the mode control motor runs
smoothly.
7P CONNECTOR
21-47

Recirculation Control Motor
Test
LDisconnect the 4P connector from the recirculation
control motor.
Connect battery power to the No. I terminal, andground the No.2 and No. 4 terminals; the recircula-
tion control motor should run smoothly.
CAUTION: Never connest ths battery in the oppo-
site direction.
Disconnect the No. 2 or No. 4 terminals from ground;
the recirculation control motor should stop at FRESH
or RECIRCULATE.
NOTE: Don't cycle the recirculation control motor
for a long time.
RECIRCULATION CONTROL MOTOR
4. lf the recirculation control motor does not run in step
2, remove it, then check the recirculation control link-
age and door for smooth movement. lf they move
smoothly, replace the recirculation control motor.
21-48
Replacement
L Disconnect the 4P connector from the recirculation
control motor, and remove the wire harness clip
from it.
Remove the two self-tapping screws and the recir-
culation control motor.
Install in the reverse order of removal. After installa,
tion, make sure the recirculation control motor runs
smoothly.
4P CONNECTOR
CONTROL MOTOR

RelaysHeater Fan Switch
Test
There should be continuity between the No 1 and No. 3
terminals when power and ground are connected to the
No.2 and No. 4 terminals, and there should be no conta-
nuity when power is disconnected.
Blower motor relaY
. Blower motor high relay ('99 00 models)
,I It;€'Y )
Test -'96 - 98 Models
Check for continuity between the terminals according to
the table below.
lerminal
Position14253
OFF
1IrJ
2o-o
3o-a
4c)-{
21-49

Mode Control SwitchPower Transistor
Test -'96 - 98 Models
Check for continuity between the terminals accordinq tothe table below.
Terminal
Position't071
Heato-o
HeaVDefo---o
Defo--o
VentG-o
HeaVVento--o
1
;l t
4
789
21-50
Test -'99 - 00 Models
1. Disconnsct the 3P connector from the oower tran-stsror.
2, Carefully release the lock tab on the No. 2 terminal inthe 3P connector, then remove the terminal and insu-late it from body glound.
Connect a 1.2 - 3.4 W bulb between the No. 1 andthe No. 2 cavity on the 3P connector.
Reconnect the 3P connector to the power translstor.
Turn the ignition switch ON fll), and check that theblower motor runs.
12V 1.2-3,1W
No. 1 laLU/aLK)