Honda Accord: A/C Signal Circuit Troubleshooting

NOTE: • If the blower motor does not run at all speeds, the A/C compressor will be inoperative. Run the self-diagnostic function, and check for DTC B1241.

Before performing any other troubleshooting, repair the cause of the inoperative blower motor.

• Do not use this troubleshooting procedure if any of the following items are operative: The condenser fan, the radiator fan, or the A/C compressor, or if the heater is inoperative. Refer to the symptom troubleshooting index.

• Before doing symptom troubleshooting, check for powertrain DTCs (see page 11-3).

1. Turn the ignition switch to ON (II).

2. Check if the blower motor operates at all speeds.

YES

-Go to step 3.

NO

-Repair the problem in the blower motor circuit (see page21-166).

3. Do the sensor input display mode (see page 21-107).

Is Sensor #5 (evaporative outlet air temperature) above 3 В°C?.

YES

-Go to step 4.

NO

-Go to step 9.

4. Turn the ignition switch to LOCK (0).

5. Disconnect climate control unit connector A (28P).

6. Turn the ignition switch to ON (II).

7. Measure the voltage between climate control unit connector A (28P) terminal No. 21 and body ground.

CLIMATE CONTROL UNIT CONNECTOR A (28P)

Wire side of female terminals

* 1 : With navigation

*2: Without navigation

Is there battery voltage? YES-

Replace the climate control unit (with navigation) (see page 21-190), (without navigation) (see page 21-191 ).

NO

-Go to step 8.

8. Measure the voltage between driver's under-dash fuse/relay box connector F (33P) terminal No. 5 and body ground.

DRIVER'S UNDER-DASH FUSE/RELAY BOX CONNECTOR F (33P)

Wire side of female terminals

Is there battery voltage? YES

-Repair an open in the wire between the climate control unit and the MICU.

NO

-Check for loose wire or poor connections at driver's under-dash fuse/relay box connector F (33P) terminal Mo. 5. if the connections are good, substitute a known-good MICU and recheck. If the symptom goes away, replace the original MICU.

9. Turn the ignition switch to LOCK (0).

10. Disconnect climate control unit connector B (12P).

11. Measure the evaporator temperature sensor resistance between climate control unit connector A (28P) terminal No. 23 and connector B (12P) terminal No. 10.

CLIMATE CONTROL UNIT CONNECTOR A (28P)

Wire side of female terminals

CLIMATE CONTROL UNIT CONNECTOR B (12P)

Wire side of female terminals

* 1 : With navigation

*2: Without navigation

Is the resistance less than 24 kO? YES-

Check for loose wires or poor connections at the climate control unit connectors. If the connections are good, substitute a known-good climate control unit and recheck. If the symptom goes away, replace the original climate control unit (with navigation) (see page 21-190), (without navigation) (see page 21-19D.

NO

-Test the evaporator temperature sensor (see page 21-58).