Honda Civic. Manual — part 732

CHECK )

2. Check the radiator cap

(see RADIATOR
CAP TEST )

3. Check the coolant

temperature

4. Check the operation of

the air mix control
motor and door (see
Air Mix Control
Motor Test)

5. Check the blower

motor for obstructions

6. Check for air leaks

around the ducts and
vents

7. Check the inlet heater

hose temperature

If it is COLD,
check for
restrictions in the
hose, a damaged
or leaking
thermostat, and a
damaged or
leaking water
pump.

If it is HOT,
check for
restrictions in the
heater core. Back
flush the heater
core or replace
heater core.

2008 Honda Civic EX

2006-08 HVAC Heating - Civic (All Except Hybrid)

SYSTEM DESCRIPTION

HEATING DOOR POSITIONS

Fig. 4: Identifying Heating Door Positions
Courtesy of AMERICAN HONDA MOTOR CO., INC.

HEATER CONTROL PANEL INPUTS AND OUTPUTS

2008 Honda Civic EX

2006-08 HVAC Heating - Civic (All Except Hybrid)

Fig. 5: Identifying Heater Control Panel 24P Connectors
Courtesy of AMERICAN HONDA MOTOR CO., INC.

WIRE COLOR AND SIGNALS REFERENCE

Cavity Wire color

Signal

1

BLK

AIR MIX POTENTIAL +5V

OUTPUT

2

-

-

-

3

ORN

MODE 1

OUTPUT

4

LT GRN

MODE 2

OUTPUT

5

PUR

MODE 3

OUTPUT

6

BLU

MODE 4

OUTPUT

7

BLU

BLOWER FEEDBACK

INPUT

8

YEL

POWER TRANSISTOR CONTROL

OUTPUT

9

-

-

-

10

-

-

-

11

-

-

-

12

RED

ILLUMI (-)

OUTPUT

13

RED

SENSOR COMMON GROUND

INPUT

14

WHT

MODE VENT

OUTPUT

15

GRN

MODE DEF

OUTPUT

16

ORN

RECIRCULATE

INPUT

17

PUR

FRESH

INPUT

18

GRY

AIR MIX POTENTIAL

OUTPUT

19

LT BLU

AIR MIX COOL

OUTPUT

20

PNK

AIR MIX HOT

OUTPUT

2008 Honda Civic EX

2006-08 HVAC Heating - Civic (All Except Hybrid)

CIRCUIT DIAGRAM

21

BLK

GROUND (G504)

OUTPUT

22

BRN

REAR WINDOW DEFOGGER RELAY

INPUT

23

LTGRN

IG2 (Power)

INPUT

24

GRY

ILLUMI (+)

INPUT

2008 Honda Civic EX

2006-08 HVAC Heating - Civic (All Except Hybrid)