Problem with A/C

antonio_santos

Original poster
Member
Apr 26, 2012
7
Hello to all Trailblazer owners. I'm a new member and would like to thank you all for letting me join this forum. I used to belong to trailvoy forum but got discouraged. Thank you all for the invitation and opportunity.

Need some guidance. During the weekend, I did some preventive maintenance to my vehicle. I changed the motor oil and replaced the oil filter, the fuel filter, and the air filter. I also replaced the spark plugs and cleaned the throttle bottle. The vehicle is running great; however, my A/C stopped working. When I turn it on, it only blows air through the floor vents, but not through the console. I have a 2004 Chevy Trailblazer Ext. I have the same problem with the rear A/C. It only blows air through the floor vents. I live in El Paso, so the weather is getting hot. I can't live without a functional A/C. I don't know if this helps, but before I did the preventive maintenance, I disconnected the battery. After I finished working on my vehicle, I reconnected the battery and then went for a cruise. That's when my A/C stopped working properly. My vehicle doesn't have a digital HVAC system. It is manual. Please help. :frown:
 

fishguy1123

Member
Dec 5, 2011
310
So, you have cold air? Just not on the other vent settings? I'm not sure but I believe it could be related to not turning the hvac to off before disconnecting the battery. I'm sure someone else will chime in to help further.
 

Blckshdw

Moderator
Nov 20, 2011
10,697
Tampa Bay Area, FL
That's true, if your blower wasn't turned off, the calibration process the first time you started the truck after reconnecting the battery could have been interrupted. You can try pulling the HVAC fuse from the rear block to reset them, then let them recalibrate (with the HVAC off) for a minute, see if that helps. As for the rear, if you set the driver's control to R, can you manipulate the roof/floor actuator from the rear controls at all?
 

antonio_santos

Original poster
Member
Apr 26, 2012
7
Correct. I do have cold air; however, it is only coming out from the floor vents. If I change the vent settings, nothing happens. Cold air keeps coming out from the floor vents. I know that there is an actuator. I was wondering if I accidentally burned it out when I disconnected the battery to do the preventive maintenance.



fishguy1123 said:
So, you have cold air? Just not on the other vent settings? I'm not sure but I believe it could be related to not turning the hvac to off before disconnecting the battery. I'm sure someone else will chime in to help further.
 

antonio_santos

Original poster
Member
Apr 26, 2012
7
I do have cold air coming out on both the front and rear; however, it is coming out from the floor vents. For the rear, I did set the control to R, and used the rear controls but nothing happens. On the rear, air comes out from the floor and not from the roof. I was wondering if I accidentally burned out the actuators by disconnecting the battery when I was doing the preventive maintenance. If I recall correctly, I forgot to turn off the A/C when I disconnected the battery.



Blckshdw said:
That's true, if your blower wasn't turned off, the calibration process the first time you started the truck after reconnecting the battery could have been interrupted. You can try pulling the HVAC fuse from the rear block to reset them, then let them recalibrate (with the HVAC off) for a minute, see if that helps. As for the rear, if you set the driver's control to R, can you manipulate the roof/floor actuator from the rear controls at all?
 

jrSS

Member
Dec 4, 2011
3,950
This shit happened to me when doing the drl killer. Except...my heat on my face was on all the time and could not change temp or where the blower was blowin. So I pulled every freakin fuse checked and replaced. Found bad hvac fuse.
 

fadyasha

Member
Dec 21, 2011
1,134
silvernclean said:
Except...my heat on my face was on all the time and could not change temp or where the blower was blowin.

Man :rotfl:!

Check the fuses like the guys said! good luck! :thumbsup:
 

AbsoluteZero

Member
Nov 21, 2011
211
In the recent past roadie posted a layout of the various ac system servos. If you look at post #3 he shows and labels their location.

http://gmtnation.com/f23/hvac-acuators-dash-removal-2193/

No upper level airflow is almost always caused by the servo labeled "Floor/Dash Vent Mode Actuator". The dash doesn't have to be removed to replace. There's instructions, as I recall, on the OS. The servos are around $30 +/-. If you are very lucky sometimes they can be reset by using this procedure:

•Place the ignition switch to the OFF position.
•Remove the HVAC B fuse (rear fuse box) for a minimum of 10 seconds.
•Install the HVAC B fuse.
•Start the vehicle.
•Wait 40 seconds for the HVAC control module to self-calibrate. DON'T TURN OFF OR CHANGE ANY HVAC CONTROLS DURING THIS PERIOD!
 

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