Honda Accord: Climate Control Switch Communication Line Circuit Troubleshooting

1. Operate the climate control system with the passenger's climate control switch in all modes.

Does the climate control system operate? YES

-lntermittent failure. Check for loose wires or poor connections at the driver's and passenger's climate control switches, and at the climate control unit.

NO-

Go to step 2.

2. Operate the climate control system with the driver's climate control switch in all modes.

Does the climate control system operate? YES

-Go to step 3.

NO

-Go to step 11.

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

4. Disconnect the passenger's climate control switch 12P connector.

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

6. Measure the voltage between body ground and passenger's climate control switch 12P connector terminal No. 1.

PASSENGER'S CLIMATE CONTROL SWITCH 12P CONNECTOR

Wire side of female terminals

Is there battery voltage? YES-

Go to step 7.

NO

-Repair an open in the LT GRN wire.H 7. Turn the ignition switch to LOCK (0).

8. Disconnect the driver's climate control switch 16P connector.

9. Check for continuity between the following terminals of the passenger's climate control switch 12P connector and the driver's climate control switch 16P connector.

12P:       16P:

No. 7    No. 4

No. 8    No. 3

No. 9    No. 2

No. 10  No. 1

No. 11   No. 5

No. 12    No. 6

PASSENGERS CLIMATE CONTROL SWITCH 12P CONNECTOR

Wire side of female terminals

DRIVERS CLIMATE CONTROL SWITCH 16P CONNECTOR

Wire side of female terminals

Is there continuity? YES

-Go to step 10.

NO

-Repair an open in the wires between the driver's climate control switch and the passenger's climate control switch.

10. Check for continuity between body ground and passenger's climate control switch 12P connector terminals No. 7, No. 8, No. 9, No. 10, No. 11, and No. 12.

PASSENGERS CLIMATE CONTROL SWITCH 12P CONNECTOR

Wire side of female terminals

Is there continuity? YES

-Repair a short to body ground in the wire(s) between the driver's climate control switch and the  passenger's climate control s w i t c h .

NO-

Substitute a known-good passenger's climate control switch, and recheck. If the symptom goes away, replace the original passenger's climate control switch (see page 21 -191 ) . 11. Disconnect the driver's climate control switch 16P connector.

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

13. Measure the voltage between body ground and driver's climate control switch 16P connector terminal No. 11.

DRIVER'S CLIMATE CONTROL SWITCH 16P CONNECTOR

Wire side of female terminals

is there battery voltage? YES

-Go to step 14.

NO

-Repair an open in the wire between the driver's climate control switch and the No. 16 (7.5 A) fuse in the driver's under-dash fuse/relay box.H 14. Turn the ignition switch to LOCK (0).

15. Check for continuity between body ground and driver's climate control switch 16P connector terminal No. 14.

DRIVER'S CLIMATE CONTROL SWITCH 16P CONNECTOR

Wire side of female terminals

Is there continuity? YES

-Go to step 16.

NO

-Check for an open in the wire between the driver's climate control switch and body ground. If the wire is OK, check for poor ground at G401 (see page 22-40J.

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

17, Check for continuity between driver's climate control switch 16Pconnectorterminal No. 13 and climate control unit connector A (28P) terminal No. 28.

DRIVER'S CLIMATE CONTROL SWITCH 16P CONNECTOR

Wire side of female terminals

CLIMATE CONTROL UNIT CONNECTOR A (28P)

Wire side of female terminals

Is there continuity? YES

-Go to step 18.

NO

-Repair an open in the wire(s) between the driver's climate control switch and the climate control unit.

18. Check for continuity between driver's climate control switch 16P connector terminals No. 13 and No. 14.

DRIVERS CLIMATE CONTROL SWITCH 16P CONNECTOR

Wire side of female terminals

Is there continuity? YES-

Repair a short to another wire.

NO

-Go to step 19.

19. Reconnect the driver's climate control switch 16P connector.

20. Reconnect climate control unit connector A (28P).

21. Press and hold the FAN UP switch, then press the OFF switch.

Is the REC button LED blinking? YES

-Go to step 22.

NO

-Substitute a known-good driver's climate control switch (see page 21-191), and recheck the function. If the symptom is still present, replace the climate control unit (see page 21-190).

22. Check the driver's climate control switch LEDs.

Are the REC button and AUTO button LEDs blinking? YES

-Driver's climate control switch is faulty, replace the driver's climate control switch (see page 21-19D.

NO

-Go to step 23.

23. Check the driver's climate control switch LEDs.

Are the REC button and DUAL button LEDs blinking? YES

-Substitute a known-good driver's climate control switch (see page 21-191), and recheck the function. If the symptom is still present, replace the climate control unit (see page 21-190).

NO

-Check for loose wires or poor connections at climate control unit connector A (28P) and driver's climate control switch 16P connector. If the connections are good, replace the climate control unit (see page21-190).