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Can we reset the HVAC control?

This is a discussion on Can we reset the HVAC control? within the Technical / Maintenance forums, part of the General Discussion category; My '03 Silverado with the manual heat/air controls is stuck blowing out of the defrost vents and a little out ...

  1. #1
    Registered User rileyl's Avatar
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    Can we reset the HVAC control?


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    My '03 Silverado with the manual heat/air controls is stuck blowing out of the defrost vents and a little out of the floor vents. I replaced the battery last week, but the problem started today. I can change the temperature and fan speed, but the airflow direction does not respond. I removed and replaced the fuses in the dash in an attempt to reset the controls and the airflow would change for a while and then go back to the defrost vents.
    I have searched and reviewed similar complaints and have not found out if the user can reset the HVAC.
    The electronics on the new GM's suck, and lucky me owns three of them.

    Is there a way to reset/recalibrate the HVAC control?
    Without going to the dealer of course.
    '03 Silverado
    Manual HVAC

    Thanks to all.

    11-17-2009 UPDATE:
    Fixed!
    I replaced the vent mode actuator located up and to the right of the gas pedal. Turned the switch on and waited a minute or two, all is good. Took about 30 minutes for the repair.

    RockAuto
    ACDELCO 1573952 (15-73952) A/C Vacuum Actuator $41.79

    This is for an '03, and the new one came with the gear/guide assy attached. The description lists "Vacuum" but of course it's electric like the one it replaces.
    Thanks for all the input!
    Last edited by rileyl; 11-17-2009 at 07:59 PM. Reason: Updated to repaired status.

  2. #2
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    Re: Can we reset the HVAC control?

    Here is what workd for me in my '05: 1. Turn all HVAC controls off normally. 2. Turn off truck. 3. Pull HVAC fuse from fuse panel on end of dash. 4. Turn key on for about a minute or two and back off. 5. Put fuse back in and give it a try. There are other methods I have found on this site that may work better for you.
    Last edited by djorgensen3; 10-22-2009 at 09:26 PM.

  3. #3
    www.subsonickustomz.com ikon's Avatar
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    Re: Can we reset the HVAC control?

    disconnect power from the unit...reapply power and start truck...the HVAC module takes up to 40 seconds to calibrate itself...you should notice it changing levels and temperatures during this time. DO NOT touch any controls while the unit is calibrating.
    .:Subsonic Kustomz Minnesota Prez:.

    www.subsonickustomz.com

  4. #4
    Registered User rileyl's Avatar
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    Re: Can we reset the HVAC control?

    I removed power via the fuses and disconnected the control unit. Same problem, the vent actuator may be bad. It moves through it's full range of motion and back again. The Temp and Recirc Actuators work fine.
    I disassembled and cleaned the Vent Actuator, I have read elsewhere that grease has caused problems, the grease inside had gotten on the IC chip and a few other components. The position potentiometer does change value as it moves, but the signal may not be making it back to the control unit.
    Anyway, after cleaning it and putting it back in, it still moves through it's range and then goes back to defrost. It does this every time the key is turned on.
    Until I can get back to it, I have disconnected the cable so that it stays on dash vents. I am thinking that I need a new actuator because this one doesn't know what position it's in, or it's not sending the signal to the controller?

    Any other info. would be great. I plan to post the fix when I find it.
    Thanks again!
    Last edited by rileyl; 10-23-2009 at 05:57 PM.
    2003 Silverado, SCLB, 4.8L 4x4
    2003 Tahoe, Z71, 5.3L
    2002 Trans-AM, WS-6, 5.7L

  5. #5
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    Re: Can we reset the HVAC control?

    Not too sure about the new ones, but the old ones was vaccuum operated. If there was a hole in the vac line, it wouldn't operate the actuator. Whatever controls the actuator may not be sending a "signal" for it to work. If it is electrical, check it with a meter while you switch from vent to defog, etc. If it is vaccuum, start truck and see if you have vaccuum.

  6. #6
    Registered User Mrgoodwrench3's Avatar
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    Re: Can we reset the HVAC control?

    There is a calibration procedure using the Tech 2. A good independent shop or dealer has this tool.

  7. #7
    Registered User rileyl's Avatar
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    Re: Can we reset the HVAC control?

    Fixed!
    I replaced the vent mode actuator located up and to the right of the gas pedal. Turned the switch on and waited a minute or two, all is good. Took about 30 minutes for the repair.

    RockAuto
    ACDELCO 1573952 (15-73952) A/C Vacuum Actuator $41.79

    This is for an '03, and the new one came with the gear/guide assy attached. The description lists "Vacuum" but of course it's electric like the one it replaces.
    Thanks for all the input!
    Last edited by rileyl; 11-17-2009 at 08:00 PM.
    2003 Silverado, SCLB, 4.8L 4x4
    2003 Tahoe, Z71, 5.3L
    2002 Trans-AM, WS-6, 5.7L

  8. #8
    Registered User boomslang's Avatar
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    Re: Can we reset the HVAC control?

    I have on 02 Tahoe. Its a long story short. After changing the starter and battery my vent actuator was out of whack from the power going crazy I guess and only blowing out the defrost vents. After pulling power to module trying to reset and pulling my hair out, I got under the dash and found the actuator gears not engaged. With power off I physically moved the the actuator and gears to the full vent position. Works normal now. Cycles through vent to defrost and back.

    Quote Originally Posted by rileyl View Post
    I removed power via the fuses and disconnected the control unit. Same problem, the vent actuator may be bad. It moves through it's full range of motion and back again. The Temp and Recirc Actuators work fine.
    I disassembled and cleaned the Vent Actuator, I have read elsewhere that grease has caused problems, the grease inside had gotten on the IC chip and a few other components. The position potentiometer does change value as it moves, but the signal may not be making it back to the control unit.
    Anyway, after cleaning it and putting it back in, it still moves through it's range and then goes back to defrost. It does this every time the key is turned on.
    Until I can get back to it, I have disconnected the cable so that it stays on dash vents. I am thinking that I need a new actuator because this one doesn't know what position it's in, or it's not sending the signal to the controller?

    Any other info. would be great. I plan to post the fix when I find it.
    Thanks again!

 

 

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