Help! Air moving through my a/c, even when it's off!

[Marauder731]

Trying to figure out why there is constantly air moving through my air conditioning, even when I turn it off! More air seems to be passing through when the vehicle is moving faster too. I've tried turning it to max ac and then turning off as my mechanic suggested but it did not solve the issue. Any ideas guys?

[fastblackmerc]

Trying to figure out why there is constantly air moving through my air conditioning, even when I turn it off! More air seems to be passing through when the vehicle is moving faster too. I've tried turning it to max ac and then turning off as my mechanic suggested but it did not solve the issue. Any ideas guys?

Could be a few things

Blend Door Actuator
EATC
Vacuum leak
Bad vacuum motor(s)

Run the EATC self-test and post any DTC's that show up.

How do you do the EATC self test you ask????

Electronic Automatic Temperature Control Module Self-Test Procedure

Interior of the vehicle must be between 40 - 90 degrees while running the test. If not you may get false in-car temperature sensor errors.

The EATC module self-test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A NGS tester must be used to retrieve these concerns.
The EATC module self-test will detect concerns in the system control functions and will display hard diagnostic trouble codes (DTCs) in addition to intermittent diagnostic trouble codes for concerns that occur during system operation. The vehicle interior temperature should be between 4°-32°C (40-90°F) when carrying out the self-test. If the temperatures are not within the specified ranges, false in-car temperature sensor DTCs will be displayed.
The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated.
To enter the self-test, press the OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within two seconds. The display will show a pulse tracer going around the center of the display window. The test may run as long as 30 seconds. Record all DTCs displayed.
If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given.
If a condition exists but no DTCs appear during the self-test, refer to the Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Improper Operation.
To exit self-test and retain all intermittent DTCs, push the blue (cooler) button. The control will exit self-test, retain all intermittent diagnostic trouble codes and then turn OFF (display blank).
To exit the self-test and clear all DTCs, press the DEFROST button. The vacuum fluorescent display window will show 888 and all function symbols for one second. Then, the EATC control assembly will turn OFF (display blank) and all DTCs will be cleared.
Always exit the self-test before powering the system down (system turned OFF).
Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.

[Marauder731]

Wow! Thanks for all that detailed info! I'm going to give it a shot tonight when it's a bit cooler out. I will let you know what happens!

[Marauder731]

Okay, I ran the EATC test. No codes came up, so I guess that's good..... However, the issue continues, I will have my guy take a deeper look in a couple weeks and let you guys know what the problem was!