Honda Civic. Manual — part 762

NO - Repair open in the wire between the No. 36 (10 A) fuse in the under-dash
fuse/relay box and the recirculation control motor.

5. Turn the ignition switch to LOCK (0).
6. Test the recirculation control motor (see RECIRCULATION CONTROL

MOTOR TEST ).

Is the recirculation control motor OK?

YES - Go to step 7.

NO - Replace the recirculation control motor (see RECIRCULATION
CONTROL MOTOR REPLACEMENT ), or repair the recirculation control
linkage or door.

7. Disconnect the HVAC control unit 24P connector.
8. Check for continuity between body ground and the HVAC control unit 24P

connector terminals No. 16 and No. 17 individually.

Fig. 39: Checking Continuity Between Body Ground And HVAC Control
Unit 24P Connector Terminals No. 16 And No. 17

Is there continuity?

YES - Repair any short to body ground in the wires between the HVAC
control unit and the recirculation control motor.

NO - Go to step 9.

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)

9. Turn the ignition switch ON (II), and check the same terminals for voltage to

body ground.

Fig. 40: Checking Voltage Between Body Ground And HVAC Control
Unit 24P Connector Terminals No. 16 And No. 17

Is there any voltage?

YES - Repair any short to power in the wires between the HVAC control unit
and the recirculation control motor. This short may also damage the HVAC
control unit. Repair the short to power before replacing the HVAC control unit.

NO - Go to step 10.

10. Turn the ignition switch to LOCK (0).
11. Check for continuity between the following terminals of the HVAC control

unit 24P connector and the recirculation control motor 7P connector.

HVAC CONTROL UNIT 24P CONNECTOR AND RECIRCULATION
CONTROL MOTOR 7P CONNECTOR

24P

7P

No. 16

No. 7

No. 17

No. 5

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)

Fig. 41: Checking Continuity Between HVAC Control Unit 24P And
Recirculation Control Motor 7P Connector

Is there continuity?

YES - Check for loose wires or poor connections at the HVAC control unit
24P connector and at the recirculation control motor 7P connector. If the
connections are good, substitute a known-good HVAC control unit, and
recheck. If the symptom/indication goes away, replace the original HVAC
control unit.

NO - Repair any open in the wires between the HVAC control unit and the
recirculation control motor.

HVAC CONTROL POWER AND GROUND CIRCUIT TROUBLESHOOTING

1. Check the No. 36 (10 A) fuse in the under-dash fuse/relay box.

Is the fuse OK?

YES - Go to step 2.

NO - Replace the fuse, and recheck. If the fuse blows again, check for a short
in the No. 36 (10 A) fuse circuit.

2. Disconnect the HVAC control unit 24P connector.
3. Turn the ignition switch ON (II).

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)

4. Measure the voltage between the HVAC control unit 24P connector terminal

No. 23 and body ground.

Fig. 42: Measuring Voltage Between HVAC Control Unit 24P Connector
Terminal No. 23 And Body Ground

Is there battery voltage?

YES - Go to step 5.

NO - Repair open in the wire between the No. 36 (10 A) fuse in the under-dash
fuse/relay box and the HVAC control unit.

5. Turn the ignition switch to LOCK (0).
6. Check for continuity between the HVAC control unit 24P connector terminal

No. 21 and body ground.

Fig. 43: Checking Continuity Between HVAC Control Unit 24P Connector
Terminal No. 21 And Body Ground

Is there continuity?

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)