Hi. I have a 2010 CX-9 and recently the rear ac/heat stopped working. It had been working sporadically recently, my wife said its not been working at all for about a month. I would like to try and fix myself and avoid the dealer. Any suggestions would be greatly appreciated.

 

Common problem is with the control unit/panel in the rear of the centre console.

 

Thank you. It has power going to the controls as i am able to change the temp and fan speed but no air is blowing out. Any idea on how to fix?

 

Insufficient air (or no air) from rear vents

DESCRIPTION
• Problem with each rear vent and/or duct
• Rear airflow mode does not change when front and/or rear climate control unit mode switches.

POSSIBLE CAUSE
• Rear vent mode malfunction
• Rear heat mode malfunction
• Rear airflow mode actuator malfunction
• Open, short circuit in wiring or poor connection between front and rear climate control unit

Diagnostic procedure

STEP

INSPECTION

ACTION

1
INSPECT TO SEE WHETHER MALFUNCTION IS IN VENT MODE
• Does air blow out when in the rear vent mode?
Yes
Go to the Step 6.
No
Go to the next step.

2
VERIFY THAT REAR HEATER CONTROL USING FRONT CLIMATE CONTROL UNIT
• Turn the rear heater to ON and OFF using the front A/C control panel.
• Is it possible that the rear heater turns ON and OFF using the front climate control unit?
Yes
Go to Step 4.
No
Go to the next step.

3
INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (OPEN, SHORT OR POOR CONNECTION OF TERMINALS BETWEEN FRONT AND REAR CLIMATE CONTROL UNIT) OR ELSEWHERE
• Inspect for open, short or poor connection of terminals between front and rear climate control unit.
― 3B—B
― 3C—C
― 3E—E
― 3I—I
• Is there any open, short or poor connection of terminals?
Yes
Repair or replace malfunctioning part, then go to Step 10.
No
Go to the next step.

4
INSPECT VENT
• Is the vent clogged?
Yes
Remove obstruction, then go to Step 10.
No
Go to the next step.

5
VERIFY THAT REAR A/C DUCT IS INSTALLED
• Is the rear A/C duct properly installed?
Yes
Inspect the duct for clogging, deformation and air leakage, then go to Step 10.
No
Install the duct securely in the proper position, then go to Step 10.

6
INSPECT TO SEE WHETHER MALFUNCTION IS IN REAR HEAT MODE
• Does air blow out when in the rear heat mode?
Yes
Go to the next step.
No
Inspect the rear vent for clogging, then go to Step 10.

7
INSPECT REAR VENT
• Is the rear vent clogged?
Yes
Remove obstruction, then go to Step 10.
No
Go to the next step.

8
INSPECT REAR MODE ACTUATOR
• (See REAR AIRFLOW MODE ACTUATOR INSPECTION.)
• Is the rear airflow mode actuator normal?
Yes
Go to the next step.
No
Replace the rear airflow mode actuator, then go to Step 10.

9
INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (OPEN, SHORT OR POOR CONNECTION OF TERMINALS BETWEEN FRONT CLIMATE CONTROL UNIT AND REAR AIRFLOW MODE ACTUATOR) OR ELSEWHERE
• Inspect for open, short or poor connection of terminals between front climate control unit and rear airflow mode actuator.
― 2P—C
― 2B—A
― 2D—E
― 1L—F
― 1J—G
• Is there any open, short or poor connection of terminals?
Yes
Repair or replace malfunctioning part, then go to next step.
No
Replace the front climate control unit, go to the next step.

10
VERIFY REPAIR
• Does air blow from the rear A/C vent mode?
Yes
Troubleshooting completed.
Explain repairs to customer.
No
Recheck malfunction symptoms, then repeat from Step 1 if the malfunction recurs.